'May never be found': grim wait for Nepal flood answers

Closure for the loved ones of many Australians and others still missing from the Nepal-Tibet floods is likely months away, while for some it may never come.

Forensic medicine expert Richard Bassed has worked to identify the dead following disasters in Australia and abroad.

The head of forensic medicine at Monash University flew to Thailand to help identify Australians lost to the 2004 Boxing Day tsunami and worked in the aftermath of Victoria's Black Saturday bushfires in 2009.

But the scale of the task confronting forensics experts in flood-ravaged Nepal was in a class of its own, he said.

"I can't imagine the difficulties," Professor Bassed, who also serves as deputy director at the Victorian Institute of Forensic Medicine, told AAP.

"The bodies they recover will probably be miles from where they lived originally, they'll be decomposed, they'll be traumatised from what happened to them.

"There will be people buried under hundreds of feet of mud and they may never be found."

Prof Bassed is not involved in the Nepal-Tibet disaster response but has been watching it from afar.

Of the work he has been involved in, he said only the 2004 tsunami - when as many as 5400 people died in Thailand alone - could compare.

"They were everywhere," Prof Bassed said of the dead washed up and down the country's Indian Ocean coastline.

Despite a year-long effort, aided by victim identification breakthroughs made during the 2002 Bali bombings, as many as 900 remained unidentified, he said.

DNA testing has significantly improved in the years since, adding to developments in imaging and facial recognition technologies, the professor said.

But he stressed Nepal's mountainous landscape and the challenges of co-ordinating international support teams, along with local resource constraints, meant the work of identifying the dead would likely end before all those missing are found.

"It's a real political decision as to how long they keep going," he said.