The Welsh government will try to opt-out of UK ministers' plans to tighten trade union strike ballot rules.
First Minister Carwyn Jones is unhappy that key parts of the Trade Union Bill relate to devolved public services such as health and education.
A vote will be held in the Senedd early in 2016 that would seek to effectively veto some clauses.
The UK government said the bill was being introduced "to make strike laws fairer for working people in Wales".
The clauses the Senedd vote would seek to veto include a requirement for a 40% turnout threshold for strike ballots in "important public services".
The legislation would also end the "check off" system, where union subscriptions are taken direct from pay packets.
"We've said repeatedly that the Trade Union Bill which the UK government has introduced to Parliament has the potential to cause significant damage to the social and economic fabric of the UK," Mr Jones said.
"In particular, I have grave concerns that it will prove socially divisive, lead to more confrontational relationships between employers and workers, and ultimately undermine rather than support public services and the economy."
"We have made clear to the UK government that, as significant parts of the bill relate specifically to public services which are devolved, it is not acceptable for them to impose it on Wales," he added.
UK Business Secretary Sajid Javid has said the bill was "not a declaration of war" against unions but necessary to stop "endless" threats of industrial action.
A UK government spokesman said the bill was about "balancing the rights of trade unions with the rights of working people and businesses".
"They have a right to expect that essential services won't be disrupted at short notice by strikes supported by only a small proportion of union members," the spokesman added.