Jailed former Malaysian prime minister Najib Razak was found guilty of abuse of power on Friday in the biggest trial yet in the multibillion-dollar 1MDB scandal, a ruling that could have significant political repercussions.

The judge had yet to deliver the full verdict and sentencing.

Malaysia and US investigators say at least $4.5 billion was stolen from 1Malaysia Development Berhad, a state fund Najib co-founded in 2009 while in office. More than $1 billion allegedly made its way into accounts linked to Najib, who has consistently denied wrongdoing.

Najib has been charged with four counts of corruption and 21 counts of money laundering for receiving illegal transfers of more than 2.3 billion ringgit ($569.45 million) from 1MDB. He had consistently denied wrongdoing.

"The contention by the accused that the charges against him were a witch hunt and politically motivated were debunked by the cold, hard and incontrovertible evidence against him that pointed towards the accused having abused his own powerful position in 1MDB, coupled with the extensive powers conferred upon him," Judge Collin Lawrence Sequerah said in an ongoing reading of the verdict.

Najib could face maximum jail terms of between 15 and 20 years on each charge, as well as a fine of up to five times the value of the alleged misappropriations.

Najib, 72, has been in prison since August 2022, when Malaysia's top court upheld a verdict convicting him of corruption for illegally receiving funds from a 1MDB unit. His 12-year jail sentence in that case was halved last year by a pardons board.

'Unmistakable bond' with fugitive financier

Najib last year apologised for mishandling the scandal while in office but had consistently denied wrongdoing, saying repeatedly that he was misled by 1MDB officials and the fugitive financier, Jho Low, about the source of the funds.

Judge Sequerah in reading the verdict had earlier said evidence had revealed Najib had an "unmistakable bond and connection" with Low, who acted as the then prime minister's "proxy and intermediary" in 1MDB affairs.

Low, who has been charged in the United States for his central role in the case, denies all wrongdoing and his whereabouts are unknown.

Najib has maintained he was misled by Low and other 1MDB officials into believing that funds deposited into his account were donations from the Saudi royal family.

But Sequerah said Najib's argument was "implausible" and dismissed letters on the donations produced by Najib that allegedly originated from the Saudi royal family, saying they were not corroborated by evidence and were probably forgeries.

"The irresistible conclusion is that the Arab donation narrative is not meritorious ... the evidence pointed unmistakably to the fact that the monies were, in fact derived from 1MDB funds," Sequerah said.

Test of govt stability

The verdict came just days after another court denied a bid by Najib to serve his jail sentence under house arrest - a decision that reignited tensions within current Prime Minister Anwar Ibrahim's administration.

Najib's party, the United Malays National Organisation, campaigned against Anwar in a 2022 election but joined his coalition to form a government after the poll ended in a hung parliament.

Some UMNO leaders expressed disappointment with the decision to deny Najib house arrest and others were angered by social media posts by some members of Anwar's coalition celebrating the earlier ruling.

Anwar on Tuesday called for calm, urging all parties to accept the court verdict with "full patience and wisdom".