Former Malaysian prime minister Najib Razak's much-anticipated trial linked to the multibillion-dollar scandal involving state investment firm 1MDB finally began yesterday after a seven-week delay.

Najib's trial at the Kuala Lumpur High Court began exactly a decade to the day after he was sworn in as premier. He earned the dubious distinction yesterday of being the first prime minister to stand in the dock.

Looking relaxed in a dark blue suit, white shirt and purple tie, the Pekan MP took a few moments to greet supporters and offer prayers when he arrived at the courthouse before heading in. His wife Rosmah Mansor, who also faces money laundering and tax evasion charges, was not with him.

In this trial, the 65-year-old former premier faces three counts of criminal breach of trust, one charge of abuse of power and three counts of money laundering involving RM42 million (S$14 million) from SRC International, a former unit of 1Malaysia Development Berhad (1MDB). The sum is a fraction of the US$1 billion investigators alleged made its way into his personal bank accounts.

Najib, who consistently denies wrongdoing and says the charges against him are politically motivated, pleaded not guilty yesterday.

In his opening statement, Attorney-General Tommy Thomas said: "The accused during his entire period in office as prime minister, at which time these offences were committed, simultaneously held the office of minister of finance, thereby combining maximum political power and control of the nation's purse."

Najib was also chairman of the board of advisers of 1MDB and adviser emeritus in SRC International, he said. "A common feature of both companies was that the true power in directing and managing their affairs did not lie with the board of directors, as is required by law and is the universal practice... but in the person of the accused."

Mr Thomas said evidence would show that in December 2014, Najib's credit card was charged US$130,625 (S$177,000) for expenses made at the luxury Chanel designer boutique in Hawaii, and personal cheques were issued for renovations at his residences in Kuala Lumpur and in his constituency in Pekan, Pahang.

Cheques were also issued to the component parties of the former ruling Barisan Nasional (BN) coalition led by Umno. As Umno leader, Najib consequently became the prime minister.

"The burden is now on the prosecution to prove beyond a reasonable doubt that the accused, Mohd Najib Abdul Razak, is guilty of the criminal charges preferred against him at this trial," said Mr Thomas.

The trial's first witness Muhamad Akmaludin Abdullah, 35, assistant registrar of the Companies Commission of Malaysia, took the stand to establish the registration of SRC International and its directors.

After a short hearing yesterday, the judge adjourned proceedings to April 15.

The trial was originally scheduled to begin in February, but appeals filed by Najib's defence team over procedural matters caused the case to be postponed a few times. Defence lawyer Shafee Abdullah even managed to get the appeal hearing pushed back after he pleaded that his pet dog had injured his arm.

Mr Shafee said the proceedings yesterday were "hardly a trial" and he remained "confident of winning the case". He denied that the defence was attempting to delay the trial and accused the prosecution of simply wanting to go on record as having started it.

He also criticised Mr Thomas' opening statement as just a "political speech" which did not outline the prosecution's case and how it would prove it.

Najib faces a total of 42 charges of corruption and money laundering involving RM2.6 billion believed to be from 1MDB that went into his personal account.

1MDB incurred crippling debts of up to RM51 billion, after an alleged US$4.5 billion was siphoned from its accounts and laundered across the globe from Singapore to the United States.

Najib's trial begins nearly a year after he was ousted in the May 9 polls, which saw the BN lose its 60-year grip on power to the opposition Pakatan alliance and the return of his 93-year-old nemesis, Tun Dr Mahathir Mohamad, as his successor.