A Hong Kong fortuneteller on Monday filed an appeal against a court ruling that denied his claim to the estimated HK$100 billion ($12.9 billion) estate of late property tycoon Nina Wang, with his counsel arguing the intimacy of the two's relationship was underestimated in the initial trial.

A painting of Nina Wang and Tony Chan.

The case had grabbed headlines for months, during which Tony Chan battled the eccentric billionaire's charity, now run by her siblings, for the huge real estate fortune that once made the pigtailed Wang Asia's richest woman.

Wang, celebrated for her outlandish attire and thrifty character, died of cancer in April 2007 at the age of 69, triggering a bitter feud between Chan and the charity, with both claiming they were entitled to her estate.

High Court Judge Johnson Lam ruled last February that a will in Chan's possession was a forgery, siding with the charity's claim to the estate based on another will.

Chan, a former bartender who claimed he was Wang's secret lover, held a series of odd jobs before starting a career advising clients on feng shui, an ancient Chinese belief system based on harnessing natural and spiritual energies.

At the start of the 10-day hearing on Monday, Chan's lawyer Ian Mill argued the judge in the initial hearing had misconstrued key evidence, including the testimony of a handwriting expert who deemed Chan's will a fake.

"The judge made fundamental errors in his approach in evaluating the evidence," Mill told the city's Court of Appeal.

"(He) was wrong in accepting there was sufficiently cogent evidence that it was a forged will."