UN chief Ban Ki-moon has said he will appoint a replacement for a Swiss judge who quit Cambodia's Khmer Rouge war crimes court amid a row with Phnom Penh about whether to pursue more suspects.
Laurent Kasper-Ansermet rocked the UN-backed tribunal in March when he became the second international judge in six months to resign over difficulties investigating two new cases strongly opposed by the Cambodian government.
Ban believes that it is "essential" that those cases "be brought back onto a positive course", spokesman Martin Nesirky said in a statement emailed to AFP late on Friday.
"The secretary general has decided, in this regard, to initiate a process for the selection of a new international co-investigating judge, and a new reserve international co-investigating judge."
Following the Swiss's shock resignation on March 19, observers said the UN would have to choose between pursuing the controversial cases with a new judge or pulling out of the troubled and perpetually cash-strapped court altogether.
Ban urged the Cambodian government to "extend full cooperation to the new judges", Nesirky added.
Reserve judge Kasper-Ansermet was the UN choice's to replace a German judge who quit in October citing government interference at the court, but Phnom Penh refused to recognise Kasper-Ansermet's appointment.
The Swiss said he was then "blocked" at every turn by his Cambodian counterpart in his efforts to probe the potential cases, which involve five mid-level Khmer Rouge members accused of mass killings and forced labour under the regime's 1975-1979 reign.
Cambodian Prime Minister Hun Sen, himself a former cadre before he defected, has long opposed going after more suspects, even telling Ban in 2010 that prosecutions beyond the current second trial were "not allowed".
The tribunal, set up to find justice for the deaths of up to two million people under the hardline communist Khmer Rouge, has so far completed just one case, sentencing a former prison chief to life in jail for overseeing the deaths of some 15,000 people.