The battle over state border closures escalated on Thursday, with premiers trading insults and One Nation leader Pauline Hanson threatening a court challenge.

Queensland, Western Australia, South Australia, the Northern Territory and Tasmania are all standing firm on their closed borders, refusing to commit to timelines to reopen them.

Queensland Premier Annastacia Palaszczuk continued to flatly reject calls to let southerners back into her state on Thursday.

“We are not going to be lectured to by a state that has the highest amount of [coronavirus] cases in Australia,” she said in Brisbane.

NSW reported two more coronavirus infections on Thursday, and has had 49 deaths. Queensland had no new cases, and has had six fatalities.

Earlier, NSW Premier Gladys Berejiklian accused the leaders of the closed states of using the move to boost their popularity.

“I’m sure those premiers are getting more popular in their states for keeping their borders closed,” she told ABC News Breakfast.

She has led the push to reopen borders, locking horns with Ms Palaszczuk and Western Australian Premier Mark McGowan.

“I don’t think it’s logical to maintain the border closures for a prolonged period of time,” Ms Berejiklian said.

“For Australia to really move forward as a nation during this very difficult economic time, as well as difficult health time, we do need our borders down.”

Senator Hanson joined in the border push on Thursday, declaring the closures unconstitutional and threatening a High Court challenge.

She said she had a constitutional lawyer who would lead the case against the state government’s border closures.

“Annastacia Palaszczuk must abide by the Australian constitution and do the right thing by Queenslanders,” she wrote in a Facebook post.

“Her actions are causing me a great deal of concern for the economic viability of our state.

“There is no cure or vaccine for the coronavirus, and until there is, all states and territories must learn to live with the virus.”

Senator Hanson said the ongoing closure breached Section 92 of the Constitution, which requires free movement of people and goods between state borders.

However, the Queensland border is still open to trade and for interstate travel on compassionate grounds.

Ms Palaszczuk appeared unconcerned by the threat of legal action.

“We are reviewing this every month, nothing has changed,” she said.

“If she [Pauline Hanson] wants to do that it’s entirely up to her.

“By the time any action got to the High Court, I’m quite sure the borders will be open.”

Federal government heavyweight Peter Dutton, a Queensland MP, also attacked Ms Palaszczuk.

He challenged her to look crumbling tourism operators in the eye and explain her hardline stance.

“There is just no logic to her position,” Mr Dutton told 2GB radio.

“If she is conducting a social experiment, well, let us know.”

But Queensland authorities have repeatedly said a September date is likely for reopened borders.

Chief health officer Jeannette Young has flagged the possibility of borders remaining shut beyond then if infections aren’t controlled.

Other states stand firm

WA, SA and the NT are also taking hardline approaches to border closures amid fears of a second wave of infections.

On Wednesday, Mr McGowan accused Ms Berejiklian of bullying.

“It might inconvenience the NSW premier and some people from the eastern states, but frankly, I don’t give a damn,” he said.

Health Minister Roger Cook said if the WA government could bring down regional borders early then it would, but federal biosecurity zones had complicated the situation.

“The police commissioner, with the state solicitor’s office, is working on the dismantling of those biosecurity zones,” he said.

“That will provide us with a much clearer landscape in order to then release further regional borders.”

On Thursday, SA Premier Steven Marshall said closed borders meant his state could move faster on reopening its economy.

“If we open up all the borders, we can really only move as fast as the slowest jurisdiction,” he said.

“On balance, we’ve formed the opinion that it’s more important for us to get people back to work in South Australia.

“Therefore we’ve made the decision to keep our borders closed and go ahead with lifting restrictions and creating work.”

South Australia has no active COVID-19 cases, and has had only one case in the past month.

Tasmanian Premier Peter Gutwein said calls for an imminent reopening of borders “don’t make sense”.

Mr Gutwein has indicated he is likely to move on Tasmania’s borders in July.

“We are in a good place, but we need to get to a better place,” he said.

It has been five days since Tasmania has had a confirmed new infection.

Australia’s deputy chief medical officer Paul Kelly has said he sees no reason for borders to remain shut “from a medical point of view”.

Australia is recording only a handful of new coronavirus cases each day and has just 535 active cases.

COVID-19 has claimed 100 Australian lives and infected more than 7000 people since the outbreak began.

Victoria reported four new cases on Thursday, three linked to its Cedar Meats abattoir cluster.

The ACT and the NT have no active cases. Western Australia has four and Queensland 12.

-with AAP