Defence Minister Marise Payne has not ruled out returning to a combat role as part of a renewed strategy to beat back the resurgent Taliban.

Four of the world's largest companies have been under investigation by the ATO, an inquiry has heard.

The Turnbull government has asked the High Court to hear questions over the validity of MPs within the next month.

Senate powerbroker Nick Xenophon has accused social media giant Facebook of not acting fast enough to stamp out fake news.

Angry Coalition MPs are blaming the citizenship fiasco and the marriage survey for another hit in the polls.

He will finish up at the Health Department in September.

Child protection campaigners say a flagship family violence inquiry is a "waste of time".

"There's so much doom and gloom in the world, it's taking a light-hearted approach to everything I suppose."

Australia will discuss potential further troop increases to Afghanistan with the United States.

The Australian Sex Party will come to an end this week, with founder Fiona Patten set to deregister the party and unveil a new political party to reach more voters.

Prime Minister Malcolm Turnbull has said he deplores the hurtful language being used against people and insists the vast majority of Australians are bringing respectful views to the public debate about same-sex marriage.

Four brothers accused of plotting to blow up an Etihad passenger flight from Sydney to Abu Dhabi were allegedly motivated by the involvement of Australia and United Arab Emirates in the war on Islamic State.

Liberal MP Ann Sudmalis has attempted to dismiss new questions over her possible dual citizenship, after an incoming passenger card from 1966 - filled out when she was 10 years old and re-entering Australia - emerged in which she listed her nationality as "British Australian".

The government still needs support from the Senate crossbench to get the program off the ground.

Australians had "little to no knowledge" of the government's efforts to stop tax avoidance.

The executives of the world's largest technology companies will be grilled by a Senate inquiry into corporate tax avoidance, as the government hopes to claw back up to $4 billion in revenue into public coffers.

Donald Trump is set to deliver a major address late morning Australian time that will almost certainly involve an increase in US troop numbers.

The next terrorist attack will "be on your head, Pauline", Greens senator Sarah Hanson-Young has told Pauline Hanson after the One Nation's burqa stunt on the floor of the Senate.

Australian forces overseas are receiving advice from the Defence Department about the same-sex marriage poll.

Turnbull government frontbenchers are publicly disagreeing with George Brandis after the Attorney-General slapped down Tony Abbott.

The High Court will have a directions hearing on the matter this Thursday.

A Turnbull government move to slash industrial chemical regulation could create "toxic chemical disasters", critics have warned.

The leader of Canberra's Catholics wants individuals to receive protections against participating in same-sex marriages.

• EXCLUSIVE

Domino's delivery driver Casey Salt is taking on her employer and one of Australia's biggest unions.

• COMMENT

Even as Nick Xenophon was confessing, he was making terrible puns. 

• INVESTIGATION

Huawei is a commercial company but has remained under a cloud because of its possible links to the Chinese government.

From architects to bar staff, Australians involved in managing crowds will be urged to plug security into their everyday thinking to prevent terror attacks under a national strategy that will embed long-term changes into the country's public spaces.

Nick Xenophon will refer himself to the High Court and his political future is in doubt after the shock discovery he is a British overseas citizen.

• EXCLUSIVE

Australia's most senior Catholic has warned the church's 180,000 employees must uphold its teachings "totally".