Prime Minister Malcolm Turnbull says he 'expects July 2' election

Prime Minister Malcolm Turnbull will wait until after the May 3 budget to ask the governor-general to dissolve both houses of parliament and call a July 2 election.

Mr Turnbull declined to be more specific about when he would make an election announcement, preferring to say it would be at an "appropriate time" after the budget.

The prime minister has until May 11 to make the call.

"But I just want to be very clear that we are governing, we have a lot of decisions to make, not least of which is the budget, the most important economic policy statement of the year," he told reporters at a construction site in Canberra on Tuesday.

Mr Turnbull has the triggers he wants for a double-dissolution election after the Senate rejected for a second time government legislation restoring the building industry watchdog.

Ultimately voters would decide the fate of the Australian Building and Construction Commission, he said.

• Budget first, then election: Turnbull

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• Turnbull has trigger for July 2 election

Mr Turnbull vowed to use an election mandate to present the legislation to a joint sitting of the new parliament.

"I think Australians understand that it's important that the rule of law prevails in every part of Australian industry," he said.

They also understood they were paying too much for schools and hospitals and roads because of lawlessness in the construction sector.

The PM was confident of his Government’s chances of re-election.

Turnbull was handed his trigger to call July election after the Senate for a second time rejected government legislation to re-establish a construction industry watchdog.

Turnbull, who wrested the leadership from conservative Liberal Party colleague Tony Abbott in September, has threatened to hold national polls for both houses of parliament on July 2 unless the Senate passed two stalled bills relating to unions.

But the Senate on Monday evening rejected for a second time legislation to reestablish a construction watchdog. It has already twice blocked a second industrial relations bill.

"The result of the decision in the Senate a short while ago... means that the constitutional grounds for a double dissolution election exist," Attorney-General George Brandis said.

But Brandis said this did not equate with Australia being in an election campaign.

"It is not really an election campaign until the parliament is dissolved and the writs are issued, in my view," he told the Australian Broadcasting Corporation.

Last month Turnbull recalled parliament to consider the bills and said if the Senate failed to pass them, he would set in train the process to dissolve both houses of parliament and issue writs for an election.

The government is set to deliver its annual budget on May 3, and Brandis said this would be a priority.

Turnbull's Liberal/National coalition government has been wavering in opinion polls, with a Newspoll published in The Australian on Monday showing the opposition Labor Party ahead of the government 51 percent to 49 percent.

But Brandis said almost all Australian elections fell within a 52-48 margin and were generally "extremely contestable by both sides".

"As we move into the home stretch, you would expect the race to tighten because that is what always happens," he said.

News break – April 19