Increased penalties for employers who fail to honour registered pay agreements or who victimise union members have been welcomed by SIPTU.
New procedures to deal with union recognition disputes have also been introduced, in line with an agreement drawn up during the Sustaining Progress negotiations.
The new provisions are set out in the Industrial Relations (Miscellanous Provisions) Act and codes of practice.
As well as offering stronger legal protection to union members, they prohibit victimisation of workers for choosing not to join a union.
The maximum penalty for a breach of the Act is a fine of €3,000 and/or imprisonment for up to six months.
SIPTU's national organiser, Mr Noel Dowling, said the increased penalties for victimisation or failing to honour registered pay agreements was a major concession won by unions in the Sustaining Progress talks.
The Act meant that workers in employments which did not recognise trade unions could secure representation on any matter affecting their pay and conditions of employment.
"They can refer their grievances to the Labour Relations Commission and the Labour Court. Determinations by the court will be binding and legally enforceable within a few months," Mr Dowling said.
"Right to bargain" procedures introduced in 2001, providing for voluntary resolution of union recognition disputes, had proved unsatisfactory to unions because of the length of time cases were taking to reach the Labour Court.
They demanded a statutory right to union recognition in the Sustaining Progress negotiations, but finally settled for a new, faster resolution process.
It enables the Labour Court to step in and investigate union recognition disputes at an earlier stage than was previously the case.
Mr Dowling said he particularly welcomed the fact that the new legislation prohibited the victimisation of workers who were active trade unionists.
"In the past an employer could dismiss a trade-union activist knowing that the only sanction he faced was the possibility of having to pay compensation to the victim for unfair dismissal at the Employment Appeals Tribunal.
"Under the new legislation the case can be brought immediately to a rights commissioner who can order the employer to cease harassing the person in question and make the employer liable to pay compensation worth up to two years' pay while having to keep the individual concerned on the payroll."
