Former Malaysian Premier Mahathir Mohamad filed a suit against scandal-plagued Prime Minister Najib Razak on Wednesday, alleging corruption and abuse of power, his law firm said, the latest salvo in Mahathir's efforts to remove Najib from office.

But it is unlikely to have any immediate impact as it will take months before any case is heard.

Najib has come under criticism over allegations of corruption linked to the debt-laden state fund 1Malaysia Development Berhad and deposits into his private accounts worth around $680 million.