Art world's $50,000 McCahon poser

Art experts and the artist's son have clashed over The Waterfall. Photo / Supplied

An art world stoush has broken out over the authenticity of a Colin McCahon painting that sold at auction for $50,000 this week.

McCahon family members say the 1966 work, Waterfall, is a mixed-media piece by their famous father.

But some experts want more rigorous checks to establish whether it is a genuine McCahon.

A spokesman for auction house Dunbar Sloane said experts raised concerns that Waterfall was a fake before Monday's sale, but Dunbar's had checked the painting's provenance with the Auckland Art Gallery.

McCahon's son William had also examined and cleared the work.

However, art dealer John Gow believes every part of the work, including its size, condition and material, is questionable.

He said he also had problems with the provenance provided when the un-named seller acquired it from the late John Monteith, an ex-Auckland antique dealer.

"The provenance, I believe, doesn't apply to that painting," Mr Gow said. "That's a tricky thing to prove or disprove, and I don't think that William looked at the painting properly.

"When I look at that painting my gut tells me it is not painted by Colin McCahon."

McCahon authority and Sydney art dealer Martin Browne backed Mr Gow.

He said a body of experts needed to be established to examine dodgy paintings.

William McCahon said he had no doubt the work was genuine.

"As soon as I saw it I realised it couldn't have come from any other hand."

His opinions were sometimes looked upon "snobbishly" by the art world, he said.

"The child of the artist isn't meant to know anything about the art."

Dunbar Sloane Jnr said that, although the work had been sold, no money had changed hands yet and ultimately the buyer would weigh the opposing evidence.

Auckland Art Gallery director Chris Saines said a panel of "McCahon police" wasn't necessary given the size of the market in New Zealand, and the degree of self-regulation by experts who checked pieces which went up for sale.