The prime minister travelled for hours across the north-west of the state, checking in on cattle farmers recovering from drought.

Driving through the small town of Cloncurry on Friday, his convoy came to an unexpected stop outside a cemetery.

Mr Morrison climbed out of the car and bound through the gates, flanked by Deputy Prime Minister Michael McCormack and a handful of bureaucrats.

The search party set out through the graveyard to track down a small sign on a metal stake.

There lay the ashes of Dame Mary Gilmore - Mr Morrison's great, great aunt.

"She was a communist - I'm not kidding," the conservative prime minister told a travelling companion.

"She was the first female employee of the Australian Workers Union - she wrote for the Australian Worker as a journalist."

Dame Mary - the female face of the $10 note - is one of Australia's most celebrated writers.

"She was a great journalist ... but she was a better poet," Mr Morrison said.

As a young school teacher in 1895, Dame Mary had moved to the "New Australia" commune in Paraguay.

She and her husband William then lived throughout Argentina shearing sheep, before earning enough money to return to Australia.

She later settled in Sydney, while her husband returned to a station east of Cloncurry, with their son eventually joining him there.

Dame Mary used the platform of a popular column to campaign for women, pensioners, the poor and indigenous people.

Mr Morrison's father - a beat cop in King's Cross - dropped in on her apartment most days.

"She died down in Sydney but wanted her ashes scattered up here with Billy," the prime minister said.

Her ashes were interred with the grave of her son and husband following her death in 1962.

Australian Associated Press