The art world is eagerly anticipating the publication of an exhaustive catalogue of Brett Whiteley's work, which is expected to confirm suspicions over the authenticity of three paintings.

Key points: The painting Moonlight on Lavender Bay will not be included in a soon-to-be released catalogue of authentic work

The painting Moonlight on Lavender Bay will not be included in a soon-to-be released catalogue of authentic work Experts warn more Brett Whiteley paintings may not be genuine

Experts warn more Brett Whiteley paintings may not be genuine Brett's former wife Wendy Whiteley has criticised auction houses for "screwing up the market"

Whiteley is Australia's most celebrated contemporary artist — two of the three most expensive Australian paintings ever sold at auction are his.

However, the publication of his catalogue raisonne — a complete account of his work, authored by Melbourne art historian Kathie Sutherland — is expected to cause both anxiety and relief for those who own his work.

Works contained in her seven-volume collection will have their market value secured, while the value of those omitted may be shattered.

Whiteley died in 1992 after a struggle with drug addiction, but new paintings continue to emerge.

Wendy Whiteley, Brett's former wife, doesn't believe all of the work attributed to her former husband is genuine.

Wendy Whiteley in her secret garden at Lavender Bay, Sydney. ( ABC News: Kathleen Calderwood )

She has a clear message for the auction houses and art dealers.

"If you're the ones selling this stuff, you're the ones who are screwing-up the market," she said.

Overlooking Lavender Bay at her house in Sydney's lower north shore, she told Background Briefing she knew collectors wouldn't want to believe her warnings about forgery, but she wouldn't blunt her criticism of the industry.

"Nobody likes to be told they've just bought a fake."

A Background Briefing investigation can reveal at least one major painting by the artist, Moonlight on Lavender Bay, previously listed as genuine by Menzies auction house but then withdrawn from sale, will not be included in the catalogue.

Moonlight on Lavender Bay has been previously listed as painted by Whiteley during 1982-1983. ( Supplied )

The ABC understands two other paintings previously attributed to Whiteley have been thrown into doubt too.

A rockstar artist, Whiteley's enigmatic life and struggles with drug addiction mean records about his work are sometimes hard to come by.

The gaps in what is known about his life has made him a target for art forgers.

Art world struggles with dubious Whiteleys

For those who trade in his work, it's become common knowledge some of the Whiteleys in circulation aren't genuine.

"With Whiteley, we know that there are between four and 10 significant oils that are reputedly by him, and that most probably aren't," Andrew Crawford, a gallery owner and dealer, said.

According to Mr Crawford, major Australian paintings are more commonly fabricated or misattributed than people think, and he believes artists like Whiteley are the perfect prey for those looking to make a buck.

"A lot of people have been fooled," he said.

There is a theory held by some art traders that Whiteley sometimes sold work on the sly.

"He lived a bohemian lifestyle," Tim Abdallah, head of art at Menzies, said.

"He exhibited his work through respectable and good galleries, but there were also pictures that were sold privately by Whiteley out the back door when he needed money urgently."

Mr Abdallah's employer, Menzies Fine Art, withdrew a Whiteley painting that it was scheduled to auction in November 2017 after concerns were raised over its provenance — the history of the painting.

Menzies Fine Art has since written an apology to Ms Sutherland for erroneously saying the work would be listed as a Whiteley in the soon-to-be-released catalogue she authored.

Mr Abdallah said the thought of being responsible for selling a fake terrifies him.

"We keep sleepless nights because of it; it's horrible," he said.

This painting attributed to Brett Whiteley was involved in a 2016 trial. ( ABC News: Stephanie Ferrier )

The climate of fear at the auction houses has been heightened since a 2016 trial, in which it was alleged two Melbourne art personalities had sold two large paintings attributed to Whiteley, and attempted to sell a third for $4.5 million collectively.

A jury found them guilty, but on appeal a judge found it couldn't be proven beyond a reasonable doubt the men charged with fraud had intentionally deceived the market.

Key evidence at the trial was provided by Jud Wimhurst, a onetime employee of art restorer Aman Siddique, one of the two men accused of staging the alleged conspiracy.

One of the paintings at the centre of the 2016 trial. ( ABC News: Stephanie Ferrier )

"There was almost a disdain towards artists. Artists got in the way of the dealers making money," Mr Wimhurst told the ABC.

"I would even question whether [the two men] were necessarily lovers of art."

He recalls how one day he stumbled upon several unfinished paintings in the style of Whiteley inside one of the rooms of Siddique's warehouse, which was usually out of bounds.

"As soon as I saw them I wished I hadn't," he explained.

"I just didn't want to be involved."

He soon resigned, but not before confiding what he had discovered to his colleague, Guy Morel.

Mr Morel's testimony would later trigger the high-profile case against Mr Siddique and his business associate, art dealer Peter Gant.

A tarnished painting

But the controversy over alleged Whiteley imitations wasn't the first time Mr Gant had been at the centre of a court case involving art fraud.

In 2010 civil proceedings, he was found to have sold fake drawings he claimed were by Robert Dickerson and Charles Blackman — two other famous Australian artists — and he was ordered to pay $300,000 in costs.

Many collectors who'd bought paintings once owned by Mr Gant, or his close associates, then sought advice on whether their prized possessions were the real deal.

One of them was Sydney art investor Rick Anderson, who said he lost half a million dollars on a Whiteley painting he bought.

Rick Anderson said the value of the Brett Whiteley painting he owned plummeted after questions of authenticity surfaced. ( ABC News: Scott Mitchell )

It was titled View from the Sitting Room Window, Lavender Bay — the auction house claimed it was from the famous series Whiteley had made from his waterfront home on north shore, Sydney.

"It was only ever recorded as owned by a private collection in Melbourne," Mr Anderson said.

"But the picture, in fact, was owned by the same people that are connected with this major issue."

When Mr Anderson tried to sell it, he said potential buyers discovered one previous owner was Mr Gant and the offers plummeted.

He had bought a $1.5 million Whiteley painting at auction and sold it privately for about $1 million.

"I had a real picture, but I had a tarnished picture. It had a stigma because of where it'd come from," Mr Anderson said.

Background Briefing has confirmed View from the Sitting Room Window, Lavender Bay will feature in the upcoming catalogue raisonne, securing its worth.