Confidence Trade Union Bill 'will be rejected' in Wales
There is confidence the Welsh assembly will reject plans to tighten rules on strike action in areas such as health and education, a minister has said.
Public Services Minister Leighton Andrews said the Trade Union Bill was "an intrusion into the devolution settlement".
There is a vote on the matter in the assembly on Tuesday.
A UK government spokesman said the bill relates to matters such as employment rights, which were not devolved.
Earlier this week, First Minister Carwyn Jones said the dispute could end up being resolved in the Supreme Court.
The bill, currently being considered by Parliament, sets new rules for industrial action including requiring 40% of those eligible to vote to back strikes in key areas such as health and education.
The Welsh government said it encroaches on its responsibilities over parts of the public sector.
AMs will vote on Tuesday on a motion which would give the assembly's approval for Parliament to legislate over devolved matters in the Trade Union Bill.
Labour, Plaid Cymru and the Liberal Democrats are expected to vote against it.
Mr Andrews told Sunday Politics Wales it was an "attack on trade unions".
"I am confident that the assembly will not give authority for the UK government to legislate in this area," he added.
Mr Andrews said if the law was passed, a bill would be introduced in the next assembly to remove the applications of its regulations in Wales.
Shadow business minister William Graham said: "I think that's a spurious argument because everybody knows that employment legislation is not devolved - end of story."
The Conservative AM said it was about giving "recognition to the individual member that their vote actually counts in a trade union dispute".
He said the assembly vote would be "ignored" by the UK government as it does not consider the matter to be devolved.
Mr Andrews also said parts of the bill aimed at changing the way trade unionists contribute to political funds, expected to significantly dent unions' donations to the Labour Party, were "vindictive".
A UK government spokesman said: "These modernising reforms fairly balance the right to strike with the right of millions of people to go about their daily lives and work.
"The Trade Union Bill relates to employment rights, duties and industrial relations, all of which are clearly reserved matters for the UK government under the Welsh devolution settlement."