Members of the Association of Garda Sergeants and Inspectors (AGSI) have voted in favour of co-operating with the Garda Reserve when the part-time force comes into operation next month.
It is understood more than 90 per cent of the AGSI's membership of 2,200 senior gardaí voted in favour of co-operation with reservists, thereby fulfilling a condition of the latest pay agreement as set by the Government.
The decision came as the first of 37 new reserves started training at Garda stations in Dublin, Cork and Galway.
Minister for Justice Michael McDowell welcomed the AGSI's decision and said he was delighted there was a "spirit of unanimity" among its members.
"I want to praise the 7,000 people who have so far come forward to offer their services to An Garda Síochána to help and support that force and I believe that it will make the professional nature of An Garda Síochána even more effective for the Irish people in the future," he said.
"All international experience shows that nobody has anything to fear in this and that everybody has everything to look forward to."
The Government previously said it would not pay gardaí their increases under the national pay agreement, Towards 2016, unless they accepted and agreed to work with the Garda Reserve.
A ballot of the 6,000 rank-and-file members of the Garda Representative Association (GRA) is due to close on November 25th and it is expected that they too will agree to co-operate with the reserve.
However, a spokesman for the association said yesterday it remained "ideologically opposed" to the part-time force.
The first group of 37 reserve trainees started training at Templemore Garda Training College in late September and will this week be deployed at Garda stations around the country. Successful trainees will graduate in December, when they are to be given the same passing-out ceremony as full-time members of the force.
Both Garda representative groups have expressed doubts about the safety of their members working alongside reservists, whom they believe will be poorly trained.
However, in September they instructed their members to co-operate with the reserve recruitment process after the Department of Justice made acceptance of the force a precondition to Garda wage increases.
Government sources believed the sending of the circular sanctioning co-operation with the recruitment process indicated the first softening in policy towards the reserve force.