A large Brett Whiteley painting was sold for $5 million in just five minutes to an unidentified Sydney family – for a grand total of $6.136 million including the buyers' premium charged by the auction house.

The sale of the painting set a new record price for an Australian artwork at an auction, and the new owners – a family from Sydney's lower north shore – remain anonymous to the wider public as they have chosen not to be revealed as yet.

The painting, Henri's Armchair, measures almost 2 metres high by 3 metres in length and is a reference to French painter Henri Matisse, who Whiteley admired.

Elizabeth Evatt sold the painting and hoped that a public institution would buy it so it could be enjoyed by the public.

"In parting with it I'm coming to terms with parting with Clive two years ago, it's a huge wrench," she said.

"To have this amazing painting in our life everyday was magnificent," Mrs Evatt said.

Her husband, art dealer Clive Evatt, died in 2018 and bought the painting directly from Whiteley in 1975.

She explained the story behind her husband acquiring the painting, as it had never been offered for sale before.

Her late husband stopped in at Whiteley's house on his way home from the races and offered to buy the work on the spot.

He led Whiteley out to his car, popped open the boot of his car and showed him his winnings from the racetrack.

The pair then grabbed the money, counted it together and the sale of the painting was done and dusted.

The auctioneer, Justin Turner, said he felt "really great" after the sale.

"This has been an amazing year for the art market, it took us all by surprise, we expected the worst when COVID hit," he said.

"I thought if we could get through the year without laying off staff that would be a success," he said.

The artist's ex-wife Wendy Whiteley, who controls his estate, said before the auction that she hoped for a good result.

"I'm not involved with it at all and I certainly can't afford to buy it," she said.

Photo credits: abc.com.au