Billionaire Eric Hotung is being sued by his son Sean Hotung, who is demanding documents relating to the secret trusts the philanthropist set up in 1979.
It is the latest twist in the son's battle to find out what happened to $100 million he says is missing from the trusts.
Sean Hotung on Tuesday filed a writ in the Court of First Instance against his father and three companies - Hillhead, Hotung Enterprises and Hotung Investment (China).
Hillhead was appointed by the senior Hotung in 1976 to look after two trusts he later set up for six of his eight children. Winnie Ho Yuen-ki, a sister of casino tycoon Stanley Ho Hung-sun, was the other trustee.
Sean Hotung is seeking access to all documents that Hotung Enterprises and Hotung Investment have relating to the trusts. Both companies were owned by the trusts.
He is also specifically demanding an account of all dealings of the trusts, including a detailed explanation about loans made with the funds to 13 debtors. The writ does not state the amount of the loans.
The billionaire revoked the trusts in 2004 after a series of lawsuits his children brought against the two trustees, beginning in 2002
Last year, the High Court dismissed his claim that he had the right to revoke the trusts.
In October last year, Sean Hotung started his battle against his father to try to find out what had happened to $100 million from the trusts.
According to the writ filed on Tuesday, Sean Hotung is requesting for an account of all dealings in relation to the trusts, including $6.5 million allegedly removed from the trusts on March 25, 1996, and transferred to his father's personal account, and $46 million paid to the trusts that was never reflected in the trust accounts.