Myanmar's government has apologised to senior Buddhist clerics over injuries sustained by monks in a police crackdown on a rally at a Chinese-backed copper mine, state media said Saturday.

Religious Affairs Minister Myint Maung said the incident at the mine in Monywa, northern Myanmar, in which at least 99 monks and 11 others suffered wounds including severe burns, was a "great grief" to the government, amid efforts to dampen public anger over the injuries.

At a ceremony with some of the country's top clerics, he "begged the pardon of wounded monks and novices", blaming the "incompetency" of the authorities, according to a report in state newspaper New Light of Myanmar.

But he stopped short of apologising for the crackdown itself, saying the demonstration had a "political" element and that the government was treating the wounded with a "clear conscience".

The pre-dawn raid on protest camps at the mine last month was the toughest clampdown on demonstrators since a reformist government came to power last year.

Photographs of the protesters' injuries have stirred outcry across Myanmar, reminding the public of brutal junta-era security tactics including the notorious crackdown on mass monk-led rallies in 2007 known as the "Saffron Revolution".

About 100 police apologised to a group of monks in Monywa soon after the recent crackdown, but the move failed to calm the public mood.

Around 150 people and 40 monks marched through Yangon on Saturday to protest the Monywa violence, the latest in a string of street demonstrations in the country's commercial hub and in the second largest city Mandalay in recent days.

"The monks are denouncing the brutal crackdown," Ye Min Oo, an activist at the rally told AFP.

"Many monks welcome the officials' apologies. But they also want them to say sorry in person to the injured monks," he said.

Opposition leader Aung San Suu Kyi has been appointed by the government to lead a probe into the incident, as well as claims of evictions and pollution at the mine.

Earlier this week she said it was not yet clear what had caused the demonstrators' injuries, but suggested tear gas could be to blame.

The dispute at the Monywa mine centres on allegations of mass evictions and environmental damage caused by the project -- a joint venture between Chinese firm Wanbao and military-owned Myanmar Economic Holdings.

Activists are calling for work at the project to be suspended to allow impact studies to be carried out, but China insists that the contentious points have already been resolved.

Several people are being held without bail at Yangon's infamous Insein prison over their involvement in other protests against the mine.

According to the New Light of Myanmar, Bhaddanta Kumarabhivamsa, one of the country's most senior monks, called upon all parties to ensure such incidents do not happen again "and try their utmost to behave themselves".