A government-appointed commission has cleared Myanmar security forces of systematic rape, murder and arson against Rohingya Muslims, dismissing UN allegations of widespread abuses during a recent crackdown.

The commission examined the deadly violence which began in northwestern Rakhine state in October last year after suspected Rohingya fighters killed nine policemen in coordinated attacks on border guard posts near Bangladesh.

In the ensuing military operation, security forces allegedly shot villagers at random, raped Rohingya women and burned down more than 1,000 houses.

Hundreds were killed.

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The commission's findings were released as the government is refusing to allow a three-member UN mission to conduct its own probe into whether the security response amounted to "ethnic cleansing" of the stateless Rohingya minority.

Giving their conclusions on Sunday, the state-backed commission revealed that any "excessive actions" were likely committed by low-rank "individual members of the security forces".

"Some incidents [of abuse] appeared to be fabricated ... others had little evidence," the commission said in a press release.

'Hundreds of deaths'

It also took aim at a detailed report by the UN's Human Rights Office released in February this year.

The UN report said it was "very likely" that crimes against humanity had been committed during the crackdown.

"The 'area clearance operations' have likely resulted in hundreds of deaths," the UN's human rights office said.

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Based on interviews with 204 witnesses who fled to Bangladesh, the UN alleged Myanmar security forces gang-raped Rohingya women, butchered children and tortured men.

The government commission refuted the UN findings, saying "no such cases were uncovered" in its work.

It also said the UN report lacked balance and failed to recognise the gravity of the attacks by Rohingya fighters.

The commission conceded that foreign media and NGOs should have been granted access to the zone during the conflict to dispel "misconceptions".

HRW: Myanmar's bullying tactics

Myanmar's government is facing increasing pressure from human rights campaigners to grant the UN investigators entry to Rakhine state.

The UN team was due to begin its work this month, but Aung San Suu Kyi's government declined to grant them visas, saying it would "only aggravate" the situation on the ground.

John Fisher, Geneva director of Human Rights Watch, said on Thursday the United Nations must stand up to "Myanmar's bullying tactics of threatening visa denials".

"Granting entry to the [UN team] would send a signal that the government is prepared to work collaboratively with the international community to help identify perpetrators of serious crimes, and deter future crimes by all parties to Myanmar's armed conflicts," he said.

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The Rohingya are reviled in Myanmar and widely seen as illegal immigrants.

Roughly one million of the Muslim group are hemmed into the impoverished border zone near Bangladesh, which remains locked down and under curfew.

On Friday, up to 50 "warning shots" were fired at a Rohingya village during a raid.

In a separate incident, the bodies of three men and three women bearing machete and gunshot wounds were discovered near the Maungdaw township in Rakhine on Thursday.

Last week, seven Buddhists were found dead in the conflict area.