The 1968 will is the last valid will and the 1990 will was not signed by the deceased

Counsel for Wang Din-shin

At the heart of the case is a hand-written will which Ms Wang says her husband made in 1990, a month before he was kidnapped from his Mercedes outside the Hong Kong Jockey Club and never seen again.

The will made her sole inheritor of Chinachem, Hong Kong's biggest privately owned property company, with interests in office blocks, cinemas and apartments.

Newspapers estimated Ms Wang's estate is now worth more than $3.5bn.

Forgery

But her father-in-law, Wang Din-shin, claims the will was forged and that he should have inherited the fortune, because of an earlier 1968 will.

Lawyers for Mr Wang, now 90, told the court his son made him sole beneficiary after hiring private detectives to find out if Nina Wang was having an affair.

Shown photographs which justified his suspicions, he made his father sole executor and trustee in a will which was kept in a bank safety deposit box.

Mrs Wang, who is represented by one of Hong Kong's most prominent barristers Martin Lee, admitted to the court in a sworn statement that she had marital troubles in 1968 but that these had been patched up.

She has issued a counter claim that a four-page Chinese will made in 1990 makes her sole beneficiary.

Mrs Wang was not in court, but her statement said her husband told her the will could only be opened after his death.

Teddy Wang was declared legally dead in 1999.

The case continues.