Hong Kong - An court battle began in Hong Kong Monday over the multi-billion-dollar fortune of Asia's richest woman, Nina Wang, who left her money to a secret lover in a disputed will.

At the opening of the case in Hong Kong's High Court, the lawyer representing Wang's family said there was "very strong evidence" that the will produced by feng shui master Tony Chan to claim her 13-billion-US dollar-fortune was a forgery.

Senior counsel Denis Chang said the will was drawn up when eccentric Wang, the former head of the Chinachem property empire, was critically ill and dying of cancer and unlikely to be well enough to sign a will.

He told the court the document upon which Chan staked his claim "invites the closest scrutiny and vigilance" and said the pig-tailed billionaire known as "Little Sweetie" never saw the feng shui master as her heir.

The highly-anticipated case will revolve around the nature of the relationship between Wang, who died aged 69 in 2007, and Chan who was known to virtually no one in Wang's circle before her death.

He claims they had a secret sexual relationship for 14 years, meeting at midnight under the pretence of arranging sessions of feng shui, a traditional Chinese practice of divining the elements such as wind and water to ensure good fortune.

Lawyers for 48-year-old Chan claimed that he and Wang shared a "long-lasting, close and affectionate love" from 1993 to her death and have produced pictures of them hugging as evidence.

Chan is expected to show more photos and audio and video recordings as evidence of their relationship as a secret "man and wife" - as well as locks of her pigtails which she allegedly gave him.

The trial is expected to last about eight weeks.

An earlier will of Wang exists, in which she leaves her estate, which is estimated at 100 billion Hong Kong dollars (13 billion US dollars) to a charitable foundation.

The alleged affair between Wang and Chan is said to have begun three years after Wang's tycoon husband Teddy was kidnapped in 1990, never to reappear.

Wang inherited the Chinachem empire after Teddy's disappearance, confounding critics by building it up into a multi-billion-dollar business conglomerate.

Ironically, she fought a long legal battle herself with her elderly father-in-law who claimed Teddy's will leaving his fortune to her was also a forgery. She ultimately won the case.

Despite her enormous wealth, Wang - who wore her hair in pigtails and wore mini-skirts well into her 60s - was notoriously frugal, once claiming she needed only around 400 US dollars a month to live. (dpa)