Myanmar's army will court-martial soldiers after a new finding in an inquiry into atrocities in Rakhine state, from which more than 730,000 Rohingya Muslims fled a 2017 army-led campaign the United Nations says was executed with "genocidal intent".

On Saturday, the website of Commander-in-Chief Min Aung Hlaing said a military court that visited the northern state found soldiers had shown "weakness in following instructions in some incidents" at a village said to have been a Rohingya massacre site.

In 2018, the Associated Press news agency reported the existence of at least five graves of Rohingya in the village, Gutarpyin, in the township of Buthidaung.

But government officials at the time said 19 "terrorists" had died and their bodies were "carefully buried".

On Sunday, military spokesman Tun Tun Nyi told Reuters the investigation's findings were secret.

"We don't have the right to know about it," he said by telephone. "They will release another statement about it when the procedure is finished."

The court, comprising a major-general and two colonels, was formed in March to respond to accusations of mass killings, rape and arson by the security forces made by the United Nations and rights groups Amnesty International and Human Rights Watch.

It visited Rakhine twice in July and August.

Myanmar forces had launched their offensive in Rakhine in response to a series of attacks by Rohingya insurgents on security posts near the Bangladesh border.

Last year a UN fact-finding mission said the military campaign was orchestrated with "genocidal intent", and recommended charging Min Aung Hlaing and five other generals with the "gravest crimes under international law".

Myanmar has denied the accusations, although Min Aung Hlaing said last month a number of security men may have been involved.

A previous military investigation in 2017 exonerated the security forces of any crimes.

Myanmar is facing growing international calls for accountability over the Rakhine campaign.

The International Criminal Court has opened a preliminary examination into the violence, while a panel formed by Myanmar that includes Philippine diplomat Rosario Manalo and Japan's former UN envoy, Kenzo Oshima, is due to publish its findings.