It takes to 10 the number of coalition MPs and senators calling time on their political careers ahead of the next election due by May.

Mr Hunt is expected to announce on Thursday he will bow out at the poll after 20 years representing the Victorian seat of Flinders.

Meanwhile, Mr Porter on Wednesday took aim at the "harshness of modern politics" as he announced he would not contest his Western Australian seat of Pearce.

Mr Porter is leaving after a spectacular fall from grace over a historical rape allegation he has strenuously denied and the use of anonymous donations to pay his legal fees for a defamation case against the ABC.

Treasurer Josh Frydenberg would like to see women selected to run in Flinders and Pearce.

"There are good female candidates who will be in the field for pre-selection," he told the Nine Network on Thursday.

"But, ultimately, those decisions will be in the hands of the pre-selectors."

Federal parliament sits for the final time this year on Thursday.

It could also be the last time parliament meets before the election, amid speculation Prime Minister Scott Morrison may call the poll just after the summer break.

The lower house is expected to continue debating the coalition's contentious religious discrimination bill on Thursday.

The Sex Discrimination Act is set to be changed to prevent the expulsion of school students because of their sexuality or gender identity in a bid to appease moderate government MPs.

But numbers for the religious discrimination bill to pass the lower house could be tight, with some Liberals still considering crossing the floor.

The laws have been referred to a human rights committee for review and it's expected to report back by February.

Labor has indicated it would withhold its position on the bill until after the inquiry as it treads carefully to avoid being wedged over the issue.

It comes after two coalition MPs, George Christensen and Llew O'Brien, on Wednesday split with the government to support maverick independent Craig Kelly's motion against COVID-19 mandates.

The government also caved to demands by Labor and the Greens over a bill to support the screen industry.

Australian Associated Press