PETALING JAYA (THE STAR/ASIA NEWS NETWORK) - Malaysian Prime Minister Najib Razak is suing Petaling Jaya Utara Member of Parliament Tony Pua and MediaRakyat portal owner Chan Chee Kong for defamation.

Najib filed the suit at the Kuala Lumpur High Court civil registry on Thursday.

A copy of the suit will be served to the defendants' solicitors on Friday.

In the lawsuit, Najib said Pua had delivered a speech at a Democratic Action Party (DAP) fund-raising dinner on Nov 3 last year relating to the 1Malaysia Development Berhad (1MDB) in which the latter slandered him.

He said the speech was then uploaded by Chan or his agents onto MediaRakyat's YouTube channel and MediaRakyat's webpage.

Najib is seeking an apology, retraction of the statement and compensation.

The development comes as the prime minister on Wednesday ordered an investigation into the accounts of 1MDB.

In a statement, Najib said the Attorney-General's report would be passed for transparent inspection to the Public Accounts Committee (PAC), which is bi-partisan.

"If any wrongdoing is proven, the law will be enforced without exception," Najib said.

The government has insisted that the strategic investment agency - whose board of advisers is chaired by Najib - had committed no wrong despite critics producing alleged internal documents and email showing at least US$700 million (S$954 million) had been siphoned off the company.