Amanda Lohrey’s eighth novel The Labyrinth has scored an enviable trifecta, collecting the $80,000 2021 Prime Minister’s Literary award for fiction.

Praised by judges as a novel of unusual gravity, deep poignancy and “considerable literary artistry”, The Labyrinth has already won the 2021 Miles Franklin and Voss literary prizes.

The Labyrinth tells the story of Erica Marsden, a mother grieving for her son who has been incarcerated for negligent homicide. After moving to a small town in south-east New South Wales to be closer to her son’s prison, Erica becomes reclusive and obsessed with the idea of building a labyrinth to make sense of her world.

Judges described the 74-year-old Tasmanian author and academic as “a writer of uncompromising artistic purpose who is never content for the novel to be mere entertainment”.

“[Lohrey] has an instinctive, if understated, sense of form and an inimitable novelist’s voice,” the judges’ statement said.

Lohrey was not present at the ceremony. Her literary agent Lyn Tranter accepted the award on the writer’s behalf and delivered a brief prepared acceptance speech that targeted the University of Sydney.

“Australian literature has never been richer or more diverse,” Lohrey wrote.

“So it was a great shock when our oldest university – Sydney – recently abolished its chair of Australian literature. I look forward to the day when the university re-establishes an institution that any self-respecting nation should be proud to showcase.”

The endowed chair position was discontinued by the university in 2019 when it lost its funding.

The Prime Minister’s Literary award for nonfiction was won by Quentin Sprague for The Stranger Artist: Life at the Edge of Kimberley Painting, which traces the decade artist and ex-gallerist Tony Oliver travelled to the East Kimberley and worked with senior Gija artists, including Paddy Bedford and Freddie Timms, and established the Aboriginal painting collective Jirrawun Arts.

The poetry prize was awarded to Stephen Edgar for his collection of poems The Strangest Place.

Grace Karskens, emeritus professor of history at the University of New South Wales, won the Australian history prize for People of the River: Lost Worlds of Early Australia.

The work examines the Indigenous people of the Dyarubbin (Hawkesbury River) and the collision of cultures that takes place when white colonisation begins – a subject similar to Kate Grenville’s acclaimed 2005 novel The Secret River. It is the second Prime Minister’s Literary award win for Karskens, who won the nonfiction category for The Colony in 2010.

The young adult literature award went to Cath Moore for Metal Fish, Falling Snow; and the children’s literature category was won jointly by Remy Lai for Fly On the Wall and Meg McKinlay for How to Make a Bird, with illustrations by Matt Ottley.

In a statement ahead of the awards ceremony on Wednesday morning, the prime minister, Scott Morrison, said since the world had been plunged into Covid chaos, “literature carries even more importance, connecting us to a range of Australian voices and bringing us closer together”.

He delivered a prerecorded speech at the ceremony, which was hosted by journalist and commentator Annabel Crabb, in which he thanked all Australian writers.

“These awards are Australia’s way of saying what you do is important, what we value is your gift to us, to our country and to the world.

“Your ability [is] to go to the heart of the matter and think deeply to find truth and to share passionately and beautifully, to open our minds reach into our souls and unleash our creative spirits. So thank you for telling our stories.”

The total prize pool of the 2021 Prime Minister’s Literary awards was $600,000. Each category winner was awarded $80,000 (the joint winners in the children’s literature category took $40,000 each), with shortlisted authors winning $5,000 each.