Perfect? Book was on both shortlists

But it was the female-chosen shortlist - which also included Margaret Atwood, Jane Smiley and Jill Dawson - from which judges chose the winner.

Sydney-based Grenville, whose previous works include Lilian's Story and Dreamhouse, was given the award during a ceremony in London on Tuesday.

The Idea of Perfection is the story of a romance between a gawky engineer with jug ears and a large woman with a ragged haircut, set in small-town New South Wales.

Grenville said she does not think it is useful to think in terms of women's writing - but that awards like the Orange Prize can help bring some women's fiction to a wider audience.

"A female prize says - look, this is terrific writing, and it happens to be by women," she said.

Atwood: Booker-winner was favourite

"My book, for example, has not been particularly highly-noticed here. It was published a year ago but now it has been read by men and women, and they both equally like it.

"So I think it is a fantastic step on the way to breaking down those stereotypes that there are certain kinds of writing that are only by women and for women."

Atwood, who won last year's Booker Prize for The Blind Assassin, had been favourite to go home with the award.

The judging panel was headed by former newspaper editor Rosie Boycott, aided by singer Suzanne Vega, journalist Kate Adie, novelist Emily Perkins and Dr Rachel Holmes of internet bookseller Amazon.

Boycott said The Idea of Perfection is an "exquisite, minutely observed study" of the two characters' lives.

Reading habits

As well as the all-female jury, an all-male panel was asked to compile a shortlist for the first time.

As part of a study on division between the sexes' reading habits, their choices had no bearing on the competition but did stir controversy in the literary world.

Jenny Hartley, of Roehampton University, said the men considered the novel as a work of art, whereas the women looked for emotional content.

"It was noticeable that the men did read for emotion but in a much more muted way - it was desirable but not necessary condition for fiction," she said.

Established awards

The men's jury comprised journalist John Walsh, novelist Paul Bailey and Carl Newbrook of Waterstone's book retailers.

The Orange Prize was created after a group of women in the publishing industry met to discuss why so few novels by females were making it to the shortlists of established awards.

The first ceremony was held in 1996, with the prize going to Helen Dunmore for A Spell of Winter.

Since then, Anne Michaels, Carol Shields, Suzanne Berne and Linda Grant have been winners.