Clive Palmer will lodge documents with the High Court this week, arguing Western Australia's border closure is unconstitutional, as the state again recorded no new cases of COVID-19.
Mr Palmer wanted to visit WA for meetings with businesspeople, Senator Mathias Cormann and potential 2021 state election candidates for his United Australia Party, but was rejected due to coronavirus restrictions.
"Closing down the border is not only an act of stupidity by WA Premier Mark McGowan, but it is against the Australian constitution and I am confident the High Court will see it that way as well," Mr Palmer said in a statement on Sunday.
"The WA premier needs to act now to ensure a successful future beyond COVID-19 by opening his borders to allow trade and travel from Australian states into WA.
"It is a matter of national importance that the borders be open."
Mr Palmer said he would lodge the legal documents on Monday and hoped to have a directions hearing in the High Court by the end of the week.
Mr McGowan said on Friday that he endorsed the WA police commissioner's decision not to grant Mr Palmer an exemption from the travel ban.
The premier has continued to insist WA's interstate borders will remain closed for months, despite criticism from some, including NSW Premier Gladys Berejiklian.
WA's coronavirus tally remains at 560, including just two active cases.
There have been more than 76,000 COVID-19 tests performed in WA.