Marathon debate wears on senators
Malcolm Turnbull has overcome a key hurdle to a July double-dissolution election with parliament passing Senate voting system changes.
But Labor, the Greens and crossbench senators are determined to make it harder for an early election to be called.
In a last-minute move on Friday, Labor forced the government to accept the Senate president would need the approval of an absolute majority of senators to bring the upper house back for a week-early budget on May 3.
The government already has two triggers for an election of the full Senate and lower house, but could get a fresh trigger if the upper house rejects a bill to reinstate the Australian Building and Construction Commission.
That debate is slated for budget day - May 10 - a day before the deadline for Mr Turnbull to call a double-dissolution poll.
But a May 3 sitting week would enable a budget to be introduced, an interim budget bill passed and some debate on the ABCC bill - which does not have Senate majority support - before a July 2 election.
A vote on the Senate voting reform shortly after 1.30pm on Friday ended nearly 40 hours of debate, making it one of the longest Senate considerations of a single bill in the past 26 years.
The government's legislation was supported by the Greens and independent South Australian senator Nick Xenophon.
Under the changes, voters will be able to allocate their own preferences above the line on the Senate ballot paper.
And if they choose to vote below the line they won't have to number every box - in some states that could be more than 100.
As well, group voting tickets will be abolished, a move crossbenchers fear will purge the Senate of micro-party senators.
Mr Turnbull declared it a "great day for democracy".
"Backroom deals and the elaborate creation of micro-parties have resulted in people being elected to the Senate with a tiny fraction of primary votes," he said.
"It has undermined the democratic reputation and credibility of the Senate, which is half of this great parliament."
Opposition Senate leader Penny Wong said it was telling the government's most urgent business was not about helping Australians but "helping themselves".
Greens support for the changes risked giving the coalition a working majority in the upper house over time.
Greens leader Richard Di Natale said smaller parties would still be able to get preferences and win seats.
However, the system would no longer throw up "shocking" results such as senators being elected with only 0.5 per cent of the primary vote as occurred in Victoria with crossbencher Ricky Muir in 2013.
Senator Di Natale said he doubted whether the government would now have time to debate the ABCC legislation before an election.
Liberal Democrats senator David Leyonhjelm and Family First senator Bob Day said their parties would preference against the Greens and coalition at the next election, which could have an impact in some tight marginal seats.
"The fightback of the minor parties starts now," Senator Leyonhjelm said.