Former Malaysian prime minister Najib Razak has failed to win a court order barring the media from discussing the merits of corruption charges against him ahead of the start of his trial.

Mr Najib has pleaded not guilty to seven charges of criminal breach of trust, abuse of power and money laundering in a case related to the alleged multibillion-dollar looting of the 1MDB state investment fund that led to his electoral defeat three months ago.

After hearing lengthy arguments from both prosecutors and defence lawyers, High Court Judge Mohamad Nazlan Mohamad Ghazali ruled that a gag on the media would be a “major incursion” on freedom of speech and expression.

He said there are existing laws on contempt and defamation, and the risk of prejudice is “quite remote” since Malaysia does not have a jury system.

“A gag order does not promote the law as an instrument of justice,” the judge said, and set trial dates spanning two months from February 12.

Mr Najib’s lawyers said they will appeal against the judge’s decision because public sentiment wanting Mr Najib to be convicted had led to many articles inferring his guilt, which could deny him a fair trial.

Prosecutors told the court they plan to call 15 witnesses during the trial.

Mr Najib, 65, has accused Malaysia’s new government of seeking political vengeance and vowed to clear his name in his trial. He did not speak to the media on Friday but wrote on Facebook a day earlier that he was confident of winning the trial.

“Through a fair trial, I am confident I can defend myself. I am confident I will be found not guilty of all the charges,” he said.

All of the charges against him involve the transfer of 42 million ringgit (£8.06 million) into his bank accounts from SRC International, a former unit of the 1MDB fund that international investigators say was looted of billions by Mr Najib’s associates.

Najib RazakNajib Razak has lost his media gag bid (AP Photo/Yam G-Jun)

Abuse of power and breach of trust carry a maximum penalty of 20 years in prison for each count. Each money-laundering count carries a penalty of up to 15 years in prison and a fine of not less than five times the sum laundered.

Mr Najib set up 1MDB when he took power in 2009 for the stated purpose of promoting economic development, but the fund amassed billions in debts and is being investigated in the US and several other countries for alleged cross-border embezzlement and money laundering.

Public anger led to the defeat of Mr Najib’s long-ruling coalition in May 9 elections and ushered in the first change of power since Malaysia gained independence from Britain in 1957.

The new government reopened investigations stifled under Mr Najib’s rule and barred him and his wife from leaving the country. Police also seized jewellery and valuables valued at more than 1.1 billion ringgit (£211) from properties linked to Mr Najib.