State borders should reopen and not close again once Australia hits an 80 per cent adult vaccination rate, according to federal Employment Minister Stuart Robert.

He claimed it would be “very difficult” for state premiers to justify such measures beyond that point.

But the federal Labor opposition labelled Mr Robert’s appearance a “bin fire”, claiming he “torpedoed” Prime Minister Scott Morrison’s claims that the national plan for reopening was locked in and unchangeable.

“The 80 per cent mark, you’d have to question why borders would be closed if lockdowns aren’t going to happen or would only be very rare and very targeted,” Mr Robert said on Sunday.

Tweet from @InsidersABC

State and federal leaders are split on when and how successful COVID suppression or mitigation methods, such as lockdowns and border closures, should end.

The national plan for reopening says that at Phase C, when at least 80 per cent of the country is vaccinated, changes may include “highly targeted lockdowns only” and exemptions from all domestic restrictions for vaccinated residents.

But the plan says nothing about when border closures should stop, and there is no firm agreement that lockdowns will never happen again.

State leaders like Queensland’s Annastacia Palaszczuk and Western Australia’s Mark McGowan say they reserve the right to use lockdowns and border closures even after hitting the 80 per cent goal.

Federal Treasurer Josh Frydenberg said last week he “cannot see the need for state borders to be closed” after that mark.

Mr Morrison has shied away from setting a specific goal for when he wants to see so-called “lockouts” end, but last week he said he believed that beyond the 80 per cent vaccination mark, “lockdowns do more harm than good”.

On Sunday, NSW Premier Gladys Berejiklian said she believed that “once we hit 80 per cent double dose, all internal borders in Australia should not exist”.

On the ABC’s Insiders on Sunday, Mr Robert said he too believed 80 per cent adult vaccination was the time to end hard state border closures.

“At 80 per cent, the national plan makes it very clear that Australians should be able to, if vaccinated, move in and out of international borders,” he told host David Speers.

“It would be pretty difficult to have travel internationally if you don’t have it interstate.”

Prime Minister Scott Morrison. Photo: AAP

Mr Morrison said last week he would be comfortable if some states with high vaccination rates opened their international border to foreign arrivals, even if other states with lower jab figures did not.

Mr Robert said state premiers should be looking to open their internal borders “as soon as they can”.

He shared his own interpretation of the plan, claiming that since the plan sets out that lockdowns should be “highly targeted”, so too should border closures.

“If lockdowns were very rare and targeted, ipso facto, you wouldn’t need state borders closed,” the minister claimed.

But lockdowns and border closures have not been used in the same way.

States with low or no COVID have used border closures to cut off travel from states with concerning outbreaks, as a preventative measure to stop virus entry, while lockdowns have been used in areas with concerning outbreaks, to prevent further spread.

The federal government has criticised state premiers who have questioned the national plan and the virus modelling from the Doherty Institute that underpins it, or who have proposed their own changes.

But Mr Robert admitted the plan was subject to amendment, saying “nothing’s set in stone”.

“A plan is always a basis for change. It has to be, because so many things have changed,” Mr Robert said.

“Anything could change next week … of course plans change.”

“But the whole point is to have a plan as a framework. We’ve got it. We should stick to it.”

It prompted heavy criticism from Labor’s shadow treasurer Jim Chalmers.

“Scott Morrison wants to pretend that we can open up at all costs. He wants to pretend that the national plan is rigid … Stuart Robert has said today that that is all rubbish,” he claimed.

“Stuart Robert has absolutely torpedoed Scott Morrison’s divisive, destructive and dishonest campaign on the national plan and the states’ role in the national plan.”

Dr Chalmers described the federal government as “a bin fire of inconsistency and incoherence”, alleging Mr Morrison had “created a climate of conflict to distract from his own failures on vaccines and quarantine”.

“It’s hard to tell who was more confused during Stuart Robert’s’ interview on Insiders this morning – the minister himself, or Australians watching at home.”