Senior cabinet ministers have reapplied pressure on states and territories to open their borders, pointing to healthcare and food supply issues.

Mr Morrison has also flagged problems with the impending bushfire season, when firefighters will have to travel across jurisdictions to battle blazes.

He expects common sense to prevail and has urged states to work together.

But the prime minister admits states and territories are extremely headstrong about their sovereignty.

"That is a very strong view held by pretty much all premiers and chief ministers," he told reporters in Canberra on Friday.

"So I can only tell you that there is some resistance."

Mr Morrison said the only border closure the Commonwealth had been involved with was between NSW and Victoria and the way they went about it provided the best model.

Earlier, Agriculture Minister David Littleproud said closures were having serious unintended consequences on agricultural supply chains.

He said health and welfare were also being affected, with cancer patients from Tenterfield in northern NSW unable to access treatment in Queensland.

A heavily pregnant woman in Moree has also been declined a permit to visit her obstetrician in Toowoomba.

Elsewhere, a Victorian pastoralist is unable to get to Broken Hill to feed and water her 500 cattle, while the flow of grain between Queensland and NSW has ground to a halt.

Tourism Minister Simon Birmingham says travel restrictions should be proportionate to the risks of coronavirus across different states.

He's urging Australians to travel if they can, to help the domestic tourism industry which has taken a $12 billion hit.

"Get out there and pretend that you're overseas and do the types of things you would do overseas while travelling around Australia," Senator Birmingham told the ABC.

He hasn't given up hope on a travel bubble with New Zealand by the end of the year but understands both nations are focused on outbreaks.

"I don't think anybody should expect there will be a breakthrough in the next few weeks or couple of months," he said.

"As we get closer to the Christmas period the calls for many people to be able to connect with family and loved ones will get greater.

"If it can be done with the concurrence of both countries we would love to see that breakthrough."

Acting Chief Medical Officer Paul Kelly does not expect international borders to reopen until a coronavirus vaccine is found.

Australian Associated Press