One of the world's largest property firms Sun Hung Kai said on Tuesday it had ousted its chairperson Walter Kwok and given the job to his 79-year-old mother after a feud at the family-run company.

"The board announces that Walter Kwok has ceased to be the chairperson and chief executive of the company and has been redesignated as a non-executive director," the firm said in a statement to the Hong Kong Stock Exchange.

Kwong Siu-hing, the widow of the company's former Chairperson Kwok Tak-seng, will become chairperson of the Hong Kong-based firm, the statement said, adding she had more than 40 years' experience in the real estate business.

There was no immediate announcement about who will become the new chief executive following the ouster, which comes the day after Walter Kwok failed in a last-ditch legal bid to prevent Tuesday's board meeting.

He has been with the firm for 33 years but has been on leave since February amid months of shadowy manoeuvring at the company, with the feud splashed across the front pages in Hong Kong newspapers.

Reports alleged the rift was caused by Walter's involvement with a female friend who had become increasingly influential on the married tycoon and his firm.

Kwok has accused his brothers Raymond and Thomas, both vice-chairpersons and managing directors of Sun Hung Kai, of falsely asserting that he had a mental disorder in order to oust him, court documents showed.

"The diagnosis made ... of bipolar affective disorder was also heavily based on misinformation as to the daily disposition of Walter Kwok supplied by Thomas Kwok and Raymond Kwok," his writ said.

Symptoms of bipolar affective disorder include marked mood swings, pressured speech, increased libido and reckless behaviour.

Walter Kwok has also sued his brothers for libel, a charge they deny.

On Monday, Hong Kong's Court of Appeal exhausted his legal options by rejecting his move to delay the latest board meeting, which was originally scheduled for last Thursday.

"The court cannot dictate to the board who should be their chairperson. The court cannot dictate to the company who should be their chief executive," Judge Anthony Rogers said in his judgement on Monday.

Walter Kwok has a colourful history, including reportedly being kidnapped in the mid-1990s by a triad gang headed by so-called "Big Spender" Cheung Tze-keung. The tycoon is said to have been held in a box for five days until a ransom was paid.

The Kwok family have never publicly admitted the kidnap, but Rogers referred to it in his judgement on Monday, saying Walter Kwok had been "kidnapped and held in the most terrible way."

Sun Hung Kai made its fortune by investing in the southern Chinese city's property market before more recently expanding to the mainland.

Its most famous building is Hong Kong's tallest — the International Finance Centre Two — which towers over the city's other huge skyscrapers.

AFP