KUALA LUMPUR: Former Malaysian premier Mahathir Mohamad filed a suit against scandal-plagued Prime Minister Najib Razak on Wednesday, alleging corruption and abuse of power, his lawyers said, the latest salvo in his 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 (1MDB) and deposits into his private accounts worth around $680 million.

He has denied any wrongdoing, maintains that he did not use the funds for personal gain and this year he was cleared of any criminal offence or corruption.

Mahathir accused Najib in the lawsuit of the "corrupt practice of carrying out various steps that were actively and deliberately taken in bad faith ... to obstruct, interfere, impede and derail the various investigations and inquiries which were being conducted by various legal enforcement agencies".

He also accused Najib of destroying "the rule of law and the sanctity of the provision of our federal constitution."

Najib's office did not immediately reply to requests seeking comment. But the minister of communications in Najib's government said Mahathir's accusations were false.

"He is clutching at straws... Mahathir has run out of options," the minister said. ?

Mahathir was joined in the lawsuit by Khairuddin bin Abu Hassan and Anina binti Saadudin, former members of the United Malay National Organisation (UMNO) which Najib heads.

Mahathir has repeatedly called for Najib to quit. He joined an anti-government protest last year, where he called for a "people's power" movement to topple Najib.

On March 4, he joined hands with long-standing foes, including the party of the jailed Anwar Ibrahim, to crank up pressure on Najib to stand down.

The plaintiffs in Wednesday's suit are seeking exemplary damages from Najib to the government of 2.6 billion ringgit ($650 million) and aggravated damages of 42 million ringgit - equal to the amounts that were allegedly deposited into Najib's bank account.

Mahathir's lawyer, Haniff Khatri, told Reuters it would take three months for the court to decide if the case would be heard.

"We don't go with empty hands, (we) have material, witnesses and we are confident of the outcome," he said.

But political analysts weren't optimistic.

"The real impact is very limited in the sense of legal terms," said Ibrahim Suffian, director of independent opinion polling firm Merdeka Center. "This is going to be battle that is drawn out for a longer period."