It is unclear what sparked the July 23 clash in central Magway region and whether all the deaths were from fighting or the sinking of a boat full of people fleeing the violence.

But Magway region lawmaker Tint Lwin said 25 bodies had been found and 13 people were still missing, adding that authorities had been hauling corpses out of the Irrawaddy River for the last two days.

"There was a serious fight," he told AFP. "I've never had this kind of experience before."

Hundreds of villagers were involved in the clashes but no one has been arrested yet as authorities carry out post mortems and try to determine what happened, he said.

The central region is about 12 hours north of the commercial capital Yangon.

State-backed Global New Light of Myanmar said a boat capsized as villagers along the river tried to leave, while survivors told local media outlets they were attacked with stones and knives.

Land ownership is extremely sensitive in Myanmar where huge swathes of the population work in agriculture.

Many villagers lack documents proving ownership despite having worked on their farms for generations.

The junta that ruled the country for almost 50 years until a democratic transition in 2011 has also been accused of rampant land grabbing.

Critics say civilian leader Aung San Suu Kyi's government has struggled to address simmering land disputes despite promises by her party the National League for Democracy.