The Garda Representative Association has rejected the terms of the Lansdowne Road Agreement.
60% of the members of the rank-and-file officers' union took part in the ballot - with 87% voting 'No' and 11% voting 'Yes'.
The GRA's Central Executive Committee will meet next week to discuss the outcome of the vote.
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It follows the Association of Garda Sergeants and Inspector's rejection of the same pay deal earlier this month.
The ASTI and the TUI teachers' unions have also both rejected the deal to reverse pay and pension cuts.