Labor will lay down the groundwork for an early election trigger if it can't clinch support for its signature housing policy as federal parliament returns.
Both houses of parliament will sit over the next fortnight after a five-week break.
The government will reintroduce the $10 billion Housing Australia Future Fund to the lower house this week, but a second vote will not be held until October.
If the housing legislation is knocked back twice within three months, the government will have the option of calling a double dissolution election.
This would result in every senator being up for re-election.
The government's announcement last week that it intends to strengthen rights for casual workers who want to become permanent employees will likely be debated during the fortnight.
The opposition has called for an industrial relations system that allows for flexibility for workplaces and staff.
It will also be the first time parliament sits since the release of the damning Robodebt royal commission report this month.
Embattled Victorian Senator David Van’s return to parliament may not take place after allegations from another woman were reported by News Corp.
Senator Van has been accused of sexual harassment and strenuously denies all claims.
He took leave for health reasons during the final sitting week before the break.
Opposition Leader Peter Dutton kicked Senator Van out of the Liberal Party room after allegations by independent senator Lidia Thorpe and former Liberal National Party senator Amanda Stoker.
Senator Van resigned from the party, writing: “I am deeply distressed and hurt that I have not been afforded procedural fairness in relation to these claims".
Independent MP Kate Chaney will introduce legislation to overhaul political donation laws, in a bid to improve transparency and reduce financial influence on parliamentarians.
The bill would require real time disclosure of donations more than $1000, expanding the lobbyist register and publishing ministerial diaries.
Ms Chaney said voters had demonstrated they wanted the major parties to be held to account.
“Australians deserve to know who is financing their political candidates," she said.
“Politicians should not be able to lie in political advertising and governments should not be able to use taxpayer money to fund big ad campaigns just before elections.
"Australians deserve better."
