The party will soon move into new digs at 160 Wharf St in inner Brisbane to expand its national and Queensland offices, a spokesperson confirmed.
The building was recently bought by a company owned by Mrs Rinehart, Australia's richest person and a financial backer of One Nation.
The party says its national head office will pay Hancock Prospecting the market rate to rent the space, described in a listing as a "striking three-storey freehold".
"Hancock Prospecting holds a range of commercial property and this building is one of them," a spokesperson for the mining company said.
"Hancock is not providing free or discounted space to any outside tenant, political or otherwise."
The deal was entirely above board, One Nation MP Barnaby Joyce told News24, defending the mining magnate's long list of investments in the party.
She previously gifted the Pauline Hanson-led party a Cirrus G7 private plane valued at more than $1.3 million.
"It's her building; it's her lease. We're leasing an offer at commercial rates," Mr Joyce said.
"If we've got an individual who has got money, they should be allowed to spend it as they see fit. If they want to support One Nation, knock yourself out."
One Nation has made no secret of its plans to dominate state elections, recently appointing its most senior media advisor, Richard Henderson, to oversee the South Australian branch led by former senator Cory Bernardi, AAP can reveal.
"Richard has been a tremendous asset to Senator Hanson and her federal colleagues since June 2021, however we can't ignore how much he loves his home state of South Australia," a One Nation spokesperson said.
The 55-year-old ran for the seat of South Brisbane at the last Queensland state election while working for Senator Hanson.
He made headlines in May over an exchange, captured by television cameras, with a Guardian Australia reporter in which he told her to "shut up" when she asked a question at an Adelaide press conference.
He later said Senator Hanson had reprimanded him for the incident.
Mr Henderson finished in Senator Hanson's office on Friday and will begin as head of media in Adelaide in three weeks.
The role within the federal office is yet to be filled.
Mr Bernardi, a Liberal until 2017, led One Nation to its most successful SA election result this year.
The party won four seats in the upper house, beating the Liberals, and three in the lower house.
It is also eyeing off seats in the Victorian election this November, as support for Labor, which has governed 33 for the last 44 years, wanes.
One Nation could end up holding the balance of power as the Liberals and Nationals need to gain 16 seats to form a majority government.
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