PHNOM PENH (THE PHNOM PENH POST/ASIA NEWS NETWORK) - More than 70 Cambodians are set to be deported to the kingdom by the United States by the end of the month, the largest batch in the history of the controversial 15-year-old programme, Cambodia's Immigration Department and advocates confirmed on Wednesday (Dec 6).

In a speech to garment workers in Phnom Penh, Prime Minister Hun Sen welcomed the "brothers and sisters" home - largely brushing aside his own previous scathing comments about the repatriation programme.

"We have an agreement with the US and we need to follow it," Hun Sen said. "For us, we thought about humanitarian issues and human rights, but we have not changed anything to not follow the agreement."

The 2002 agreement became a flashpoint in Cambodian-US relations after the kingdom temporarily stopped accepting deportees last year, leading the US to impose visa sanctions on top Cambodian foreign ministry officials.

The dispute briefly put Hun Sen and rights advocates on the same side, with both criticising the programme as inhumane. Many of the returnees, most of whom went to the US as refugee children, have never set foot in Cambodia and were not aware they were not US citizens at the time they committed the criminal offences that precipitated their deportation.

Ministry of Interior immigration head Sok Phal said yesterday that an estimated 72 people are in the process of being deported, but said he did not know when they would arrive.

Bill Herod, head of the Phnom Penh-based Returnee Integration Support Centre, said the NGO is expecting the first batch of deportees to land by the end of the month and a second group shortly thereafter.

"This is the largest group we've ever received," Herod said, adding that it is "very disheartening to see these numbers".

"It's a matter of international law. It's terrible and we all hate it and wish it weren't that way, but the fact is these are Cambodian citizens, not US citizens."

Hun Sen, in his speech, also promised he would "not allow anyone to mistreat" the deportees, in reference to reports of abuse at the Australian detention centres for asylum seekers on Nauru and Manus islands.

The refugees and asylum-seekers on Nauru and Manus have the option of coming to Cambodia under a controversial 2014 deal, but few have taken up the offer - an issue the Premier said he recently brought up with Australian Prime Minister Malcolm Turnbull.

"He said that the problem is that no one wants to come to Cambodia, and it is true," Hun Sen said. "They want to live in Australia... he said that his opposition party said that when they win the election, they will be allowed to live in Australia."

The US Embassy declined to comment on Wednesday.