The Senate is expected next week to pass laws to allow same-sex marriage, but the citizenship crisis won't be off the agenda.
With Malcolm Turnbull scrapping the House of Representatives sitting which was scheduled to start on Monday, the upper house will be left on its own to deal with a private senator's bill introduced by Liberal Dean Smith to change marriage laws.
It follows a national survey which returned a 61.6 per cent "yes" vote.
The bill is expected to pass with coalition, Labor and crossbench senators having a free vote.
The Senate won't immediately launch into the marriage debate on Monday.
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The first order of business will be to refer Nick Xenophon Team senator Skye Kakoschke-Moore to the High Court after she discovered she held dual citizenship by descent.
The court is already scheduled to initially hear the cases of former Senate president Stephen Parry and crossbench senator Jacqui Lambie on December 8.
Senators have been set a deadline of 5pm AEDT on December 1 to lodge declarations that they are only Australian citizens and provide family history and details of any renunciation of dual citizenship.
If the same-sex marriage laws are passed before Wednesday night, it is possible the Senate could return to its regular program, including private senator's business, on Thursday morning.
In which case, Queensland senator Barry O'Sullivan could find himself with an opportunity to introduce a bill to set up a commission of inquiry into the banking, insurance, superannuation and financial services sector.
Labor, the Greens and some crossbenchers have said they would consider supporting the bill, but its prospects of getting through the lower house are less certain.
Cabinet and shadow cabinet are due to meet on Monday, but the joint party room and Labor caucus won't meet on Tuesday because the lower house is not sitting.
New Greens senator for Western Australia, Jordon Steele-John, will deliver his first speech on Wednesday.
An estimates committee hearing - which will examine the Registered Organisations Commission, Fair Work Ombudsman and the Australian Building and Construction Commission - has been scheduled for December 1.
