Low-paid workers in certain sectors will eventually have greater protection for their pay and conditions.
It comes after Minister for Jobs, Enterprise and Innovation Richard Bruton implemented reforms to the sectoral wage-setting mechanisms known as Joint Labour Committees.
Since 1946, the JLCs saw employers and unions agree legally binding wages and working conditions for around 200,000 employees.
They cover a number of lower-paid sectors, including catering, contract cleaning and hairdressing.
However, the JLCs were found to be unconstitutional some years ago, giving rise to fears that lower-paid workers would lose certain protections and see their pay and conditions deteriorate.
A Labour Court review recommended certain reforms, some of which have been implemented today.
While certain protections will be retained for vulnerable workers, the Government said the new JLC regime would "enhance wage flexibility" to improve competitiveness.
Employers and unions in the various JLC sectors must now negotiate the terms of each sectoral agreement.
Minister Bruton said JLC reform was necessary to make the system fairer and more responsive to changing economic circumstances and to support job creation.
He said the revised framework would allow employee representatives and employers to come together voluntarily to negotiate terms and conditions for workers in their respective sector.
He said that under the JLC system, employers would be able to agree and set minimum pay and conditions, and agree work practices custom-made to their industry with a flexibility that could not be achieved through primary legislation.
Unions described the development as a good day for low-paid workers.
SIPTU Vice President Patricia King said the union expected employers in the six relevant sectors, hospitality, catering, retail, contract cleaning, security and agriculture, to take a full and productive part in the process of negotiating the new agreements.
Mandate General Secretary John Douglas said the re-establishment of the JLCs meant thousands of low-paid vulnerable workers would be protected and it would ensure that the concept of decent work was put back on the agenda.
However, employers' organisation Ibec has criticised the decision.
Its head of human resources relations, Maeve McElwee, said: "The JLC system should have been consigned to history.
"This unnecessary regulation will undermine the ability of employers to create and sustain jobs in this economy."
The orders signed today by Mr Bruton will halve the number of JLCs. Two JLCs covering Dublin Hotels and Law Clerks will be abolished.
There will be amendments to the existing JLCs covering contract cleaning, hairdressing, hotels (outside of Dublin and Cork) and the security industry.
Officials are examining how to amend the Agricultural Workers JLC, which is more legally complex than the others, as it was established under primary legislation.
The current scope of the JLCs in catering or the retail grocery trade will remain unchanged.