KUALA LUMPUR (Nov 11): A Malaysian judge ordered former Malaysian premier Najib Razak to defend himself against a charge of abuse of power in the trial involving a former unit of troubled state-owned investment firm 1Malaysia Development Berhad (1MDB).

Najib appeared in a Kuala Lumpur court on Monday, when the judge announced that the case, his first to go to trial, will proceed.

The former prime minister's involvement in the ex-1MDB unit was "pervasive and imperious" and his conduct showed personal interest beyond that of the public office, the judge said.

Najib has consistently denied any wrongdoing.

Attorney-General Tommy Thomas's success in building a strong enough case against Najib is key to Prime Minister Mahathir Mohamad maintaining public support.

Tun Dr Mahathir returned to power last year on a campaign to oust Najib and bring those responsible for the 1MDB scandal to justice.

Since the hearing started in April, prosecutors have called dozens of witnesses, including a central bank official and a former cabinet minister, to argue Najib engaged in a "planned, premeditated criminal breach of trust case" that ran over many years.

His lawyers said he had been misled by others, including fugitive financier Low Taek Jho, more popularly known as Jho Low, who faces his own set of charges linked to 1MDB.

The current case, which revolves around seven corruption charges, hinges on whether Najib knew the RM42 million ($13.8 million) deposited in his accounts came from a former unit of 1MDB known as SRC International Sdn.

Prosecutors had said it was "incredible" for Najib to say he wasn't aware of the sum sent to his accounts since he made no police reports and didn't sue the bank for wrongful deposit.

His lawyers argued there was no link between the sum and Najib's decisions related to SRC, which they said would mean the funds don't constitute a bribe and the charges should be dismissed.