A trade union has warned employers of an "industrial war" if they try to renege on pay and pension agreements with workers.
It comes after the High Court yesterday deemed legislation allowing for the setting of legally enforceable pay and conditions for workers in various employment sectors to be unconstitutional.
The Connect Trade Union, which represents workers in construction and engineering, said it would take "stringent action" against employers that try to use the ruling to to break from previously-agreed Sectoral Employment Orders.
Connect's general secretary Paddy Kavanagh said they had written to all stakeholders to ask them to continue to honour the agreements that have been in place. He said a failure to do so would "end the industrial peace, which benefits us all at this time."
"Employers are now on notice that we will consider an attack on any one sector or worker in that sector an attack on all," he said.
Meanwhile the Unite union has called on the Government to an immediate seek a stay of the court's decision pending an appeal to the Supreme Court.
It also called for robust emergency legislation to protect workers' terms and conditions should an appeal be delayed for any reason.
Unite's regional officer Tom Fitzgerald said the timing of the ruling "threatens the incomes of tends of thousands of workers and thus puts our economic recovery at risk".
He also said it opened the door for workers to take industrial action, which could be damaging to employers.
Yesterday's ruling strikes down legislation from 2015, which was put in place to address flaws in the 1946 Industrial Relations Act, which in 2013 was itself deemed unconstitutional in how it dealt with sectoral wage-setting mechanisms.
The Sectoral Employment Orders fixed legally binding minimum rates of pay conditions including a sick pay scheme, pension contributions for all employers in the sector - including those who had not been party to the negotiations.
Employers breaching the terms could face criminal prosecution.
However a body called National Electrical Contractors Ireland (NECI), representing small to medium-sized electrical firms, challenged both the Industrial Relations (Amendment) Act 2015, and a 2019 SEO for the electrical contracting sector made under the legislation.
Yesterday a spokesperson for the Minister for Business, Enterprise and Innovation, which oversees the Labour Court, said the detailed judgment was currently under review, and that the Department was not in a position to comment on the ruling until the matter had received proper consideration.