Officials involved in the identification of the victims of last month's plane crash in Nepal predicted that it could take months to complete DNA tests, especially of the 12 foreigners.

The foreigners include four Chinese citizens, seven United Kingdom citizens and a United States citizen.

"We are facing problems due to the lack of proper DNA testing facilities as there are just two DNA testing centers here in Nepal, which failed to identify the bodies properly," said Harihar Wosti, who heads the Department of Forensic Science at the Tribhuvan University Teaching Hospital in Kathmandu.

Nineteen passengers and crew members were killed in the Sita Air plane crash on Sept 28, which happened within four minutes of takeoff and about 500 meters away from the runway.

On Sunday, government officials said that one of the deceased foreigners was a US citizen. Wu Hui - earlier identified as a Chinese citizen - was later found to be a US citizen of Chinese origin.

The officials said that the confusion over the victim's nationality emerged because travel agents failed to provide copies of the victims' passports on time.

The bodies of five Nepalese citizens, including crew members, were handed over to family members on Sunday night.

Families identified them from dental records and some possessions found on them, including jewelry.

The remaining bodies will stay in the Tribhuvan University Teaching Hospital until the DNA samples are tested and matched, or until their families provide conclusive evidence to identify them.

Wosti said that the DNA samples will need to be sent overseas for testing and that the process could take months.

So far, no authority has stepped forward to coordinate the process, and no arrangements have been made to expedite the collection and testing of samples, he said.

"DNA is a complicated thing. We need a very good lab and very good manpower. How fast it can be done depends on the lab. If they prioritize it they can do it in a week, but otherwise it could take months," he said.

Wosti and his colleagues are considering sending the DNA samples to a laboratory in Calcutta, India.

"We are also preparing to establish identification of the victims through teeth samples, so that DNA tests can be done more quickly," Wosti said.

"We've sent out a form requesting details on birth marks, jewelry, spectacles, clothes and tattoos to the victims' families in the UK, China, the US, and Nepal," Wosti added.