The day in federal parliament

TODAY IN FEDERAL PARLIAMENT

* Parliament returns on Monday for a four-day sitting week after a fortnight's break.

* The sitting coincides with a High Court challenge to the government's postal survey on same-sex marriage.

* The Senate will refer the eligibility of deputy Nationals leader Fiona Nash and independent Nick Xenophon - both dual citizens by descent - to the High Court.

* Question time in both chambers at 2pm.

WHAT'S MAKING NEWS

* Australia has condemned North Korea's latest nuclear test and called on the United Nations to take further action against the "dangerous pariah regime".

* Labor is preparing to cause chaos in parliament, especially if Barnaby Joyce is made acting prime minister later this week.

* Senate President Stephen Parry is expected to formally push for a stricter dress code after One Nation Leader Pauline Hanson wore a burka in the upper house chamber.

* Malcolm Turnbull has gained the biggest personal lead over Bill Shorten since last year's election, leading 46-29 per cent as preferred prime minister in the latest Newspoll.

* West Australian Liberal Party members have passed a WAxit motion for a committee to examine if the state could become financially independent.

WHAT'S ON THE AGENDA

*The House of Reps: MPs resume debate on government bills including for liquid fuel emergencies; electoral law changes; abolition of Limited Merits Review for electricity companies; welfare reform.

* Senate: Senators resume debate on government bills for protecting vulnerable workers; repeal of four-yearly reviews; migration law changes; broadcast media ownership changes.

ARGY-BARGY

* Government spin: Our determination is that no Australian family should be paying more for their electricity than they need to pay.

* Opposition attack: It is absolutely untenable that Barnaby Joyce should be the acting prime minister while a cloud continues over his eligibility to sit in the parliament

WHAT THEY'RE SAYING

"North Korea's reckless conduct poses a grave danger to global peace and security." - the PM.

TWEETED

@sarahinthesen8: WAxit? Really? Just sounds WAcky.