Parliament to return early on April 18

Prime Minister Malcolm Turnbull has threatened to bring on a July double-dissolution election if the Senate doesn't use a recalled session of parliament to pass key anti-trade union legislation.

Mr Turnbull has won vice-regal approval to have parliament recalled on April 18 and sit for three weeks.

The budget has been brought forward to May 3, a week earlier than scheduled.

Mr Turnbull wants the Senate to pass a bill restoring the Australian Building and Construction Commission - rejected once by the upper house - and another bill imposing tougher governance measures on trade unions that has been rejected twice.

"The go-slows and obstruction by Labor and the Greens on this key legislation must end," he told reporters in Canberra on Monday.

If the Senate passes both bills there would be no double-dissolution election.

"What we are doing here is giving the Senate ample time - this is three weeks - this is plenty of time to consider the bills, and pass them," the prime minister said.

"If they don't want to pass the bills then they should resolve to reject them and then the decision will be left to the Australian people."

Mr Turnbull said it was an opportunity for the Senate to do its job of legislating rather than filibustering.

"I make no apology for interrupting senators' seven-week break to bring them back to deal with this legislation."

If there is a double-dissolution election it would be on July 2.