Hong Kong police are investigating bank deposits which a complainant said were linked to Malaysian Prime Minister Najib Razak, police said on Friday (Sept 11) as a probe into a troubled Malaysian state investment fund widens.

The investigation comes as another blow to Datuk Seri Najib, Reuters agency said. Najib Razak chairs the advisory board of 1Malaysia Development Berhad (1MDB). The Swiss authorities recently froze millions of dollars in Swiss bank accounts linked to the firm on suspicion of corruption and money laundering.

Hong Kong police confirmed that they were probing a matter which a complainant had linked to Mr Najib, Reuters said further.

"A man reported to the police on Aug 30 and requested the police's investigation on some bank deposits," Hong Kong police said in a statement. "Investigations by Crime Headquarters are under way."

The complaint was lodged by Mr Khairuddin Abu Hassan, a former member of PM Najib's Umno party who was sacked from the party earlier this year.

A vocal critic of Mr Najib, Mr Khairuddin told Reuters he said in the report that deposits of over US$250 million (S$353 million) had been made into a Credit Suisse bank account in Hong Kong through four companies linked to the Malaysian premier.

But a Malaysian government spokesman dismissed these latest allegations as "baseless and politically motivated lies".

"The Prime Minister does not control any Credit Suisse bank accounts in Hong Kong, whether in his name or the name of the companies mentioned," the spokesman said.

(With inputs from Reuters)