Myanmar has been in chaos since the February 1 coup which ousted Aung San Suu Kyi's civilian government and ended the country's decade-long dalliance with democracy.

More than 1,400 civilians have been killed as the military has cracked down on dissent, according to a local monitoring group, and numerous anti-junta militias have sprung up around the country.

Hun Sen's foreign minister has warned the country contains "all the ingredients for civil war" and international rights groups and local anti-junta activists have urged him to cancel the two-day visit.

But the veteran leader, whose country currently holds the rotating chairmanship of the Association of Southeast Asian Nations (ASEAN), said he would go, and was willing to extend his trip if it would help defuse tensions.

He will travel with his deputy prime minister and foreign minister, and hold talks with junta chief Min Aung Hlaing, according to a Cambodian government statement.

On Wednesday Hun Sen called for a ceasefire, saying "all relevant parties must stop violence".

International powers have piled diplomatic pressure on Myanmar's military administration -- officially called the State Administration Council -- with even traditional allies such as China lukewarm in their support.

ASEAN has sought to shed its reputation as a toothless talking shop and take action on Myanmar, with leaders agreeing to a "five-point consensus" last year.

In October, the bloc took the highly unusual step of excluding Min Aung Hlaing from a summit, in response to an ASEAN envoy being denied a meeting with Suu Kyi.

But there has been little tangible progress in ending the turmoil in Myanmar. In the latest atrocity, more than 30 people were killed on Christmas Eve in a massacre blamed on the military.

There was a protest against Hun Sen's visit in northwestern Saigang region and Amnesty International has condemned the trip, saying it may do more harm than good.

"If Hun Sen truly wants to help, he should cancel this trip and lead ASEAN to strong action to address the country's dire human rights situation rather than indulge in empty gestures," Amnesty's Emerlynne Gil said in a statement.

The junta has justified the coup by alleging electoral fraud in 2020 elections, and Suu Kyi is facing a raft of charges that could see her jailed for decades.

burs-pdw/axn/jfx