Artist Anneke Jamieson, a mother of three who decided to leave her career in defence, says she was inspired by her own experiences to create the winning painting, titled The Promotion.

"My choice was difficult but obvious and, in the end, empowering," she said in her artists' statement.

The Napier Waller Art Prize, open to current and former Australian Defence Force personnel, was awarded at Parliament House in Canberra on Thursday.

The judges' decision was unanimous.

Mrs Jamieson said the painting was not a self-portrait but a picture of a successful servicewoman, dedicated to her soldiers, who had returned from maternity leave changed in ways she couldn't imagine.

"This promotion might be her greatest challenge yet," Mrs Jamieson said.

"I dedicate her to the mothers that serve, to their sacrifices and conflicted hearts and to the families who support them."

Mrs Jamieson said that in the army she found that despite support from her husband and the institution, she could not resolve her struggle to be both the officer and the mother she wanted to be.

The Promotion was selected from a shortlist of 14 artworks and will be added to the collection of the National War Memorial.

An exhibition of 14 highly commended works from the competition is on show at Parliament House in Canberra until November 20.

Voting for the $5000 People's Choice Award will continue online until the exhibition closes.

Australian Associated Press