Rules making it harder to call strikes in public services will be scrapped in Wales under Welsh Government plans.
Welsh Labour has pledged to ditch restrictions on industrial action in the NHS, the fire service, schools and other devolved services.
The UK government said people had “a right to expect protections from undemocratic strike action”.
One key restriction in the Westminster law is to allow strikes only if they are backed by 40% of a union’s members in a ballot.
Welsh ministers have denied seeking to satisfy Labour’s trade union funders, saying public sector employers supported the plans.
The Welsh Government insisted the assembly has the power needed to change the law on taking industrial action, despite earlier rows with the UK government.
The Welsh bill will also overturn changes to the time allowed for union officials to spend on union work, and to the way union members pay their subscriptions.
But it will not overturn a new threshold for turnout in ballots, which requires half of union members to cast a vote before industrial action can take place.
Finance Secretary Mark Drakeford told BBC Wales it was “absolutely not the case” that Labour was acting in the interest of unions, rather than the public.
“Employers in our public services are in support of the way we are bringing this bill forward,” he said.
“They see that this is the right way to do things for Wales as well.”
He added: “Of course the unions have a legitimate interest in this but the employers and the assembly were both in support of the way we are doing things as well.”
Before the 2016 assembly election, most AMs voted against applying the Trade Union Act to Wales, with only the Conservatives voting in favour.
The UK and Welsh governments disagreed over whether the assembly’s permission was needed before the new rules applied to workers in Wales.
Welsh Conservative leader Andrew RT Davies said: “These proposals will do nothing to improve public services in Wales – this is just the union barons calling in favours in return for bankrolling the Labour Party.
“Across Wales, workers are getting sick and tired of being held to ransom by union general secretaries, and they won’t be impressed if this proposed bill leads Wales further down the road towards regional pay scales.”
Mark Reckless, UKIP AM for South Wales East, told BBC Radio Wales that said he supported the UK legislation.
“It strikes me that the union paymasters of Labour are using taxpayers’ money to essentially fund themselves,” he said on Good Morning Wales.
“Trade unions [in] the public sector pay the Labour party money, the Labour party then ensures that money from the NHS goes to pay running the unions in that workplace.
“That is wrong.”
Dominic MacAskill, head of local government in Wales for Unison, told the programme his union considered the Westminster act as “a top-down politicised attack on trade unions”.
“It’s not just the right to take industrial action, its also looking to restrict the ability for trade unions to represent their members in the workplace,” he said.
Mr MacAskill said the act was “going back to the old 80s and 90s approach to trade unions”.
“That’s not how we work in Wales,” he added, saying there was a “progressive consensus” with Plaid Cymru and the Liberal Democrats also opposed to the UK legislation.
The Welsh Local Government Association’s employment spokesman, Councillor Peter Rees, welcomed the proposal, saying: “We respect the work of trades unions and the rights of their members.
“We want to continue to engage with them constructively to support and sustain local government services in Wales.”
‘Undemocratic strike action’
The UK government said: “We will examine the Welsh Assembly’s proposed legislation when it is introduced but we remain clear that decisions over industrial relations law is a matter for UK government.
“Ordinary working people have a right to expect protections from undemocratic strike action and the Trade Union Act will do just that.
“The assembly will have to explain to the Welsh public why it wants to repeal these.”