Same-sex marriage and the future of dual-citizen senators will dominate the return of federal parliament.
During the winter break, a small group of Liberal MPs have been advocating for the party to drop support for a plebiscite on same-sex marriage, and instead allow a free vote on a bill in parliament.
However, conservative Liberals and Nationals MPs are urging Prime Minister Malcolm Turnbull to stand by the plebiscite which was taken to the 2016 election.
One of the rebels, Sydney MP Trent Zimmerman, says they worked hard to offer a plebiscite but the Senate wouldn't back the plan.
"It's not a choice between the plebiscite as we promised it and a parliamentary vote; it's a choice between a parliamentary vote and doing nothing," he told Sky News on Sunday.
He and backbench colleagues Dean Smith, Tim Wilson, Warren Entsch and Trevor Evans have circulated a draft bill to Liberal MPs, hoping the proposed religious protections will sway them in favour of a parliamentary vote.
Liberal MPs will thrash out their differences at a meeting on Monday afternoon, ahead of a joint party room meeting with the Nationals on Tuesday.
The Senate will open on Tuesday with a statement from President Stephen Parry and the government asking that former minister Matt Canavan be referred to the High Court to test whether he is eligible to sit after he discovered last month his mother registered him as an "Italian resident abroad" a decade ago.
Section 44 of the constitution bans MPs from being dual citizens, but Senator Canavan has initial legal advice his lack of consent could save his job.
The Greens are expected to refer Larissa Waters and Scott Ludlam to the court, having resigned their Queensland and WA seats over dual citizenship.
It is also expected One Nation senator Malcolm Roberts will be referred over his British links.
The House of Representatives will debate laws to strengthen requirements for citizenship.
Mr Burke said Immigration Minister Peter Dutton had overreached and badly misread community sentiment, particularly on plans to toughen English language proficiency requirements.
"This change is a real change in how we operate as a nation," Mr Burke told Sky News, saying migrant communities felt betrayed.
He's heard many people liken the new proposal to the dictation test notoriously used under the White Australia policy to stop non-whites immigrating to the new nation.
"Of all the countries with English as an official language, the five countries with a predominantly white population are the only countries where you won't have to sit this test," he said.
"You can imagine the volcanic reaction that many communities are having to that."
