Aid workers praised Myanmar's regime on Monday for its speedy response to the recent earthquake that killed more than 70, in contrast to the aftermath of previous disasters to strike the country.

The powerful 6.8 magnitude quake struck near the borders with Thailand and Laos late on Thursday leaving an official toll of 75 dead, including one woman in Thailand.

"The government's response was very fast, it must be stressed," said Vincent Hubin, country head of the UN Office for the Coordination of Humanitarian Affairs (OCHA) based in Yangon.

"They put up considerable resources, as was the case with Cyclone Giri, when they saved many lives," he added, referring to a disaster in the west of the country in October 2010 that killed more than 40 people.

The junta was widely criticised for refusing foreign assistance for weeks after Cyclone Nargis wrought devastation across the Irrawaddy Delta in May 2008, leaving more than 138,000 people either killed or missing.

Chris Herink of charity World Vision, which is working in areas of Shan state affected by the latest quake, also said at the weekend that the government's cooperation had been proactive.

He and Hubin both said a major concern was now clean water supplies.

"It worries us that there might be contamination of water -- this is something that is going to require very careful attention," Hubin told AFP, adding that the government had begun to try cleaning wells with chlorine.

A Myanmar official told AFP that the death toll might reach about 100, but there was as yet no confirmed increase.

"The rescue teams with military members are still trying to help people around these areas," he said, declining to be named.

An unnamed Red Cross worker in Tachileik was quoted by exile news group the Irrawaddy on Sunday saying that at least 150 people had been killed.

Hubin was unable to give any estimates but said rescue teams had not yet reached all the villages, which were also at risk of landslides from current heavy downpours.

"Teams must reach these villages before the rainy season begins," he said. "We are still in the dry season and it's already difficult now."