Clive Palmer's bid to re-open WA border could succeed

Billionaire Clive Palmer's High Court case to bring Western Australia's hard border crashing down is "highly likely" to succeed, Prime Minister Scott Morrison has said.

Western Australia's border restrictions remain the toughest in the country.

"It annoys the hell out of me that Mr Palmer and the Liberal Party want to bring it down," Premier Mark McGowan said.

Mr Morrison said the government was not supporting Mr Palmer, but Mr McGowan said the Commonwealth could and should have provided evidence to help WA's border case.

"(Mr Palmer is) a very selfish and self-centred person and he's prepared to risk everyone's health just for his own travel arrangements," Mr McGowan said.

But Mr Palmer dismissed the premier's accusations.

"We would expect Mark McGowan to say that," he said.

"The state of WA and its people will be cruelled for decades if the state doesn't open its borders."

Commonwealth witness Dr Peter Collignon said the hard border was a bad idea because it offered Western Australians a "false sense of security within the state", which could lead to a faster spread if there was an outbreak.