PLEASE NOTE: EDIT CONTAINS CONVERTED 4:3 MATERIAL

An appeal by the former head of Cambodia's Tuol Sleng torture centre ended with his convictions upheld and his jail term extended to a life sentence.

Kaing Guek Eav, also known as Duch, was originally handed a 35-year term, commuted to 19 years for time spent in military detention.

Survivors of the notorious Khmer Rouge 'killing fields' regime of the 1970s welcome the ruling of the U.N.-backed court.

SOUNDBITE: Bou Meng, Tuol Sleng survivor, saying (Khmer):

"I'm 100 per cent satisfied with the court's decision and I say to the world that this trial chamber is an example of a world court."

SOUNDBITE: Chum Mei, Tuol Sleng survivor, saying (Khmer):

"This is the right decision. The decision by the appeal court is 100 per cent right and it brings justice 100 per cent."

Duch was convicted in 2010 of murder, torture, rape and crimes against humanity.

He'd argued that the court had no jurisdiction to try him because he wasn't a top commander of Pol Pot's regime.

Prosecutors who in turn appealed with civil parties in the case against what they saw as a light sentence were satisfied with the outcome.

SOUNDBITE: International co-Prosecutor Andrew Cayley saying (English):

"We were successful in the two major prongs of our appeal, we were successful in ensuring that the cumulative conviction is overturned."

The court is currently hearing the trials of three top members of the Khmer Rouge regime.

Campaigners say there's overwhelming evidence to pursue two more suspects but the government is resisting any further indictments.

Paul Chapman, Reuters