Opening hours could be cut at all Wrexham county borough council libraries rather than shutting three earmarked for closure as a way to make budget savings.
Councillors took the decision despite a recommendation to close libraries at Rhosllannerchrugog, Gresford and Brymbo to save £92,000.
Opponents outside the Guildhall meeting had called for a rethink on closures.
The council says it faces a £45m budget shortfall over the next five years.
On Tuesday Wrexham's executive board agreed to consult on its wide-ranging cuts programme, which it hopes to implement by January.
But it left the fate of the library and information service to be discussed by the homes, environment and communities scrutiny committee yesterday, with a report saying "significant financial savings" could be made.
As well as the three potential closures, another option on the table was reducing library opening hours by about a quarter.
The scrutiny committee's recommendation will go out to consultation and still has to be ratified by the executive board before opponents can consider the threatened libraries to be safe.