1) Why this issue comes up

In practice, gaps happen: the regular secretary is on leave, the plantilla item is vacant, a session must proceed, or the mayor’s office needs someone to sign routine papers. A common “quick fix” floated in local government is to tap an elected local councilor (sanggunian member) to serve as acting secretary—whether as:

Secretary to the Sanggunian (secretary of the local legislative body), or
Local Secretary in the executive side (often meaning city/municipal secretary or similar administrative office), or
Barangay Secretary (for barangay-level operations), or
A session-only secretary pro tempore (someone who just records minutes for that meeting).

The legal answer depends heavily on what “acting secretary” actually means in the specific situation—because “acting” can be used loosely, while the law treats appointments/designations to public office very strictly.

2) Core rule: elective officials are generally barred from appointment/designation to another public office during tenure

Philippine public law strongly discourages an elected official from being placed—by appointment or designation—into another public position while still serving the elective term.

A) Constitutional policy (general)

The Constitution’s civil service principles (and long-standing doctrines on incompatibility and conflicts) underpin a practical rule: an elective official should not be inserted into an appointive post during the term, even “in an acting capacity,” because that creates:

conflict-of-interest risks (especially if the sanggunian exercises oversight over the executive),
blurred separation of powers in the LGU (legislative vs executive),
circumvention of qualification, merit, and civil service appointment rules,
pay and audit issues (extra compensation, allowances, and COA disallowances).

B) Local Government Code policy (general)

The Local Government Code (RA 7160) is built around role separation:

The sanggunian enacts ordinances, approves budgets, conducts inquiries, and exercises oversight functions.
The executive (governor/mayor/punong barangay) administers and implements.
Secretaries (sanggunian secretary, city/municipal secretary, barangay secretary) are typically appointive/career or at least administrative support positions—meant to be filled by qualified personnel.

Bottom line: A councilor’s eligibility to serve as “acting secretary” is usually no, if the arrangement is a true appointment/designation to a public office or position.

3) The critical distinction: “acting” can mean three different things

When people say “acting secretary,” they may mean:

(1) Temporary performance of tasks (no formal designation to an office)

Example: A councilor helps draft minutes, assists in clerical work, or temporarily signs an attendance sheet—without being formally placed into the secretary position.

This is not automatically lawful, but it is less risky if it is purely incidental and does not amount to occupying the office or exercising the legal authority reserved to the secretary by law.

(2) Designation as Officer-in-Charge / Acting Secretary (formal assignment to a public position)

Example: A memo or resolution states: “Councilor X is designated Acting Secretary of the Sangguniang Bayan for 3 months.”

This is the usual “acting” arrangement—and it is where the ineligibility problem becomes acute.
Even if it’s “temporary,” a designation that installs an elective official into an appointive position is generally treated as legally problematic.

(3) Session-only “secretary pro tempore” (parliamentary expedient)

Example: During a particular session, because the sanggunian secretary is absent, the body chooses a member to record proceedings for that meeting only.

This can be the narrow situation where an elected member may lawfully function as a recording officer for that session, without being appointed/designated to the plantilla office of secretary.
The key is that it is a procedural measure for one sitting (or limited sittings), not an assumption of the public office with its continuing duties.

Practical takeaway: Many arrangements fail because they are framed as a formal designation (“acting secretary”), not a narrow session-only stopgap.

4) Specific contexts

A) Councilor as Acting Secretary to the Sanggunian

What the sanggunian secretary is

The secretary to the sanggunian is the institutional memory and custodian of:

minutes and journals,
ordinance and resolution records,
numbering, publication/transmittal steps,
certifications (e.g., “true copy,” “duly approved,” “approved on ___”),
administrative support that can carry legal consequences.

This is not just clerical work; it often involves official certifications and custody of legislative records.

Eligibility analysis

If “acting secretary” means a formal appointment/designation of the councilor into the secretarial office:

Generally not allowable. The councilor is an elective official and should not be placed into an appointive administrative post during the term, even temporarily.

What can be done instead (law-safe alternatives)

Designate a qualified employee from the sanggunian staff (or the LGU workforce) as acting secretary, consistent with civil service and local administrative rules.
Use a session-only secretary pro tempore arrangement only to keep a meeting going, with the official secretary (or authorized staff) later regularizing and maintaining custody of records.

The “secretary pro tempore” idea (narrowly acceptable use)

A sanggunian can adopt internal rules allowing:

a member to be chosen as temporary session secretary solely to record proceedings when the secretary is absent.

But:

avoid giving the councilor continuing custody of records,
avoid signing certifications that the law expects from the secretary as a continuing office,
avoid any formal “designation” that looks like filling the position.

B) Councilor as Acting City/Municipal Secretary (executive branch)

Here, the incompatibility is even sharper. A city/municipal secretary (or equivalent executive administrative post) is within the mayor’s administrative control and supports executive functions.

A councilor serving as acting executive secretary raises:

separation-of-powers conflict (oversight vs implementer),
potential self-review and influence over executive transactions,
civil service appointment issues.

General rule: A councilor should not be designated as acting city/municipal secretary.

C) Councilor (Kagawad) as Acting Barangay Secretary

Barangay officials are also elective, and the barangay secretary is typically an appointive administrative post. The same logic applies:

A kagawad being made “acting barangay secretary” as a designation to the office is generally not proper.
A barangay can instead assign duties to existing staff or appoint/designate qualified personnel consistent with applicable rules.

5) Compensation and audit risk: where “acting” becomes expensive

Even when LGUs attempt to justify “acting” arrangements as mere “additional duties,” problems multiply when any of these occur:

payment of an “acting allowance,” honorarium, or additional compensation,
double compensation for essentially two positions,
use of the “acting” title to justify signatory authority with financial implications.

These create high COA disallowance risk, and can lead to:

refund issues,
administrative liability for approving officials,
questions on the validity of actions signed by an ineligible “acting” officer.

A common mistake is thinking: “No extra pay, so it’s fine.” Even without extra pay, the legality of the designation itself can still fail if it effectively installs an elective official into another public office.

6) Validity of acts: are documents signed by an ineligible “acting secretary” void?

This is where people panic—but the legal landscape is more nuanced.

If the “acting secretary” is not legally eligible to occupy the position, actions can be challengeable, especially where the secretary’s certification is a statutory step (e.g., attestations required for official records).
However, for public stability, Philippine law often recognizes doctrines that protect third parties who relied in good faith on official acts done under color of authority (commonly discussed under “de facto officer” principles).

Still, relying on that is a last resort, not a compliance strategy. The better practice is to avoid creating the defect.

7) Practical compliance guide for LGUs

If you need continuity for sanggunian sessions:

Use a staff member as acting secretary where possible.
If truly unavoidable for a single session: adopt a rule allowing a secretary pro tempore for that session only, and have official custody and certifications handled by the authorized secretary or qualified staff as soon as practicable.

If the plantilla position is vacant:

Fill it through proper appointment processes (qualification standards, civil service compliance).
Use an acting/OIC from within qualified personnel—not an elective official.

Avoid these red flags:

A memo/designation naming a councilor as “Acting Secretary” of an office,
“Acting secretary” signing financial/HR documents or certifications that attach continuing legal responsibility,
Any additional compensation tied to the acting role.

8) One-sentence rule you can safely apply

A local councilor is generally not eligible to be appointed or designated as an acting secretary of a public office (legislative or executive) during the elective term; at most, the body may use a narrow, session-only secretary pro tempore arrangement to record proceedings, without treating it as an appointment to the secretarial office.

If you want, paste the exact scenario (e.g., “SB Secretary on leave; vice mayor wants Councilor A as Acting SB Secretary via memo for 60 days”) and I’ll apply the framework to that fact pattern and show the cleanest legally defensible option.