A war-crimes court in Cambodia has ruled that Nuon Chea, former deputy of the late Khmer Rouge leader Pol Pot, is fit to continue to stand trial, after the death of one of his co-defendents renewed fears that the elderly suspect may not live to see the verdict.

"The accused Nuon Chea is fit to stand trial," Judge Nil Nonn said at the UN-backed court after speaking with medical experts on Friday.

Despite the defendant's "advancing age and frailty", he said, he "remains capable of meaningful participation in his own defence".

Nuon Chea, 86, is the most senior surviving leader of the communist regime which oversaw the "Killing Fields" era in the late 1970s. He did not attend the hearing due to poor health, a clerk told the court.

Nuon is on trial with Khieu Samphan - the former Khmer Rouge head of state who is 81 - over war crimes and genocide charges.

Charges denied

Among the charges the pair face is the forced movement of people - a policy under which cities were emptied by the Khmer Rouge government - and the execution of as many as 3,000 former military officers, whose remains were found in mass graves in Cambodia's west.

The defendants deny the charges.

The death on March 14 of Khmer Rouge co-founder Ieng Sary at the age of 87 intensified fears that the surviving pair may also die before verdicts can be reached in their trial, which began in June 2011.

Ieng Sary's widow Ieng Thirith, the regime's former social affairs minister, was freed in September after being deemed unfit for trial due to dementia.

Nuon Chea has suffered a number of illnesses, including high blood pressure, acute bronchitis and heart disease, prompting his defence team to argue that their client was too weak to stand trial.

Led by "Brother Number One" Pol Pot, who died in 1998, the Khmer Rouge wiped out nearly a quarter of Cambodia's population through starvation, overwork or execution from 1975-79, in a bid to create an agrarian utopia.

The tribunal, however, has been dogged by funding shortages since it was set up in 2006 and was hit by a strike by local staff earlier this month over unpaid wages.

Salary arrears

About 270 Cambodian employees at the UN-backed court - including drivers, prosecutors and judges - have not received their salaries for this year and had threatened to walk out at the start of April.

Last-ditch talks between the UN-appointed fund-raiser for the tribunal and Cambodian officials and international donors, however, have secured funds to pay wages through April, averting the strike.

"A temporary financial solution" has been reached after the "urgent meetings", Lars Olsen, a UN spokesman, said.

Judge Silvia Cartwright confirmed that funding for the Cambodian staff had been "secured through to the end of April" and that "discussions are under way to stabilise funding from that point on".

The Cambodian side of the hybrid tribunal - whose top donors include Japan, the European Union and Australia - urgently needs around $7m to cover costs for 2013.