NSW and Queensland are at loggerheads over coronavirus border closures, with Pauline Hanson threatening to resolve the spat in the High Court.
One Nation leader Pauline Hanson is threatening to drag an escalating spat over coronavirus border closures into court, with a constitutional law expert saying the Queensland senator raises an "enormously interesting" point.
NSW Premier Gladys Berejiklian is pushing to stimulate economic activity by opening state borders but Queensland Premier Annastacia Palaszczuk is reluctant to follow suit.
Senator Hanson intervened as the spat flared up on Thursday morning, threatening to go to the High Court to open the borders.
"It is unconstitutional for Premier Palaszczuk to close Queensland's border and her actions are causing me a great deal of concern for the economic viability of our state," she wrote on Facebook.
"One Nation will not let the self-interest of this lawless premier override the constitution of our nation."
University of Queensland constitutional law professor Nicholas Aroney said Senator Hanson was referring to section 92 of the constitution, which deals with trade and the movement of people between states.
Professor Aroney said the High Court would need to decide whether closing borders and restricting the movement of people was a proportionate response.
The case for keeping borders closed could become weaker as the number of infections plummets, he said.
"Public health is a legitimate objective and the next question is whether the measures are proportionate. The seriousness of the situation is relevant to that," he told SBS News.
"As time goes by the case for restrictions becomes weaker and weaker. But that depends on a close analysis of epidemiological and public health details."
Professor Aroney said similar measures restricting the movement of people between states had been successfully challenged in the past.
Ms Berejiklian said it was crucial to re-open the borders to give states an economic shot in the arm.
However, Ms Palaszczuk has said she would not "be lectured to by a state that has the highest amount of cases in Australia".
She also said the legal challenge would be irrelevant because borders would be open before it got through the court.
Home Affairs Minister Peter Dutton weighed into the stoush on Thursday morning, urging Ms Palaszczuk to reconsider keeping borders closed.
Queensland chief health officer Jeannette Young said the border could remain shut beyond September if infections were not controlled.
Western Australia, South Australia and the Northern Territory are also keeping their borders shut for now.
"It might inconvenience the NSW premier and some people from the eastern states, but frankly, I don't give a damn," WA Premier Mark McGowan said.
Independent senator Jacqui Lambie has been pushing for Tasmania to reopen its borders.
Dr Paul Kelly, a federal deputy chief medical officer, has said there is no medical reason to keep borders shut.
"From a medical point of view, I can't see why the borders are still closed," he told reporters.
Additional reporting by AAP.
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