The country's largest craft union, the Technical Engineering and Electrical Union (TEEU), has become the latest group to accept the national pay agreement.
The union's 40,000 members joined Siptu, Impact and other smaller trade unions in endorsing the deal. Members vote 82 per cent to 18 per cent in favour of Towards 2016which will see pay increases of around 10% over the next 27 months.
But Owen Wills, TEEU general secretary, warned that already some employer bodies were causing difficulties.
"Our members voted for the national agreement in spite of inflationary pressures they are suffering, because they felt the greatest priority was to deal with the social problems created by the present boom," Mr Wills said.
"But I believe this Government and the employers are still reluctant to honour in full the measures in Towards 2016."
Mr Wills claimed a Government appointed employer regulator, the Electrical Contractors Safety and Standards Association, was advising members they did not have to abide by, or co-operate with, statutory terms and conditions set down by the industry and underpinned by Towards 2016.
He said: "Unless these commitments are met in full, they will find themselves entering a very different industrial relations environment when pay talks resume."
The TEEU's acceptance comes on the back of Siptu and Impact voting in support of the agreement.
With 40,000 members, the TEEU is the largest union in the electrical contracting industry and the second largest union in the manufacturing and construction sectors.
Mr Wills also expressed his disappointment at a lack of local bargaining for workers. "If commitments on employment standards are not addressed in full, if rogue employers are not brought to heel and if inflation is not brought under control there can be no future for national agreements," he said.
"Social partnership has to be more than a one-way street which allows big business and developers to reap the benefits of economic growth from workers and consumers through inflated prices and gross profiteering."
With around 300,000 of the country's workers now prepared to back Towards 2016it is likely to be ratified by the Irish Congress of Trade Unions next month.
Siptu, which holds around 20 per cent of voting power at ICTU, will now cast its votes in favour of the agreement at the special Congress conference on September 5th. Impact holds 10 per cent of the votes.