Mr Callum, who trained in Sydney and New York, is a three-time Archibald Prize finalist and won the Black Swan Portrait Prize in 2015.

His oil on linen creation entitled Meg attracted the acclaim of Guardian Australia art critic and guest judge Dr Andrew Frost, who made the announcement at Friday’s opening of the exhibition at the Bega Valley Commemorative Civic Centre in Bega.

Mr Callum will pick up $50,000 for the award win, Australia's richest prize for realistic portraiture.

He said the win was completely unexpected.

"My wife is going to be amazed!” he said following the announcement.

Mr Callum said he wanted to capture the essence of a young girl transitioning into adolescence and beyond and the maelstrom of emotions that comes with that time of life.

He said he hoped visitors to the Bega Valley Regional Gallery will feel as if Meg is in the room with them.