Rudd can now call a double dissolution election any time until August 11.

This time, with a double dissolution, all the Senators' seats will be contested.

Prime Minister Malcolm Turnbull promised his double dissolution election would clean out the Senate.

Eventually, Malcolm Turnbull used the rejected ABCC legislation as the trigger for a double dissolution election.

The preselection took place before the double dissolution so it applied to a half Senate election.

But the double dissolution scenario seems more likely and this option holds several benefits for Mr Turnbull.

He began his defence against the internal critics questioning his decision to call the double dissolution election.

Her counterpart on a Senate ticket in a double dissolution election would be former Democrats leader Andrew Bartlett.

And the only way you get that joint sitting is with a double dissolution, Beazley told Sky television.

So he has a parliamentary future that stretches ahead for up to six years, assuming there's no double dissolution.

The double dissolution election in 2016 further muddies the water, virtually cutting the current parliament's term down by six months.

If the Senate blocks the bill, Abbott has promised to call a double dissolution of parliament to break the deadlock.

A July double dissolution election would have to be called almost immediately after the budget, with the latest possible date being 16 July.

Turnbull does not even have the numbers to pass the industrial legislation that was the ostensible reason for calling a double dissolution election.

At a double dissolution that figure is roughly halved to 7.7% -or just 24,000 votes.

Photo: AFP Malcolm Turnbull has now left Government House in Yarralumla, where he was expected to request a double dissolution election for 2 July.