The March 28 magnitude-7.7 quake near the central city of Mandalay killed nearly 3,800 and has left tens of thousands homeless as the summer monsoon season approaches.

Monitors say junta aerial bombardments breached the first truce in April -- with the Britain-based Centre for Information Resilience logging 65 strikes, many in quake-hit regions.

A statement from the junta information team on Tuesday said the new armistice "to continue the rebuilding and rehabilitation process" would last until the end of May.

The military -- which seized power in a 2021 coup -- warned the array of ethnic armed groups and anti-coup fighters it is battling that it would still strike back against any offensives.

"We have to protect the towns and people's lives by using air strikes," a military officer in the eastern state of Karen told AFP on condition of anonymity.

"We are sorry that residents have to flee from their towns and villages because of fighting," he added.

"Locals know very well which groups are threatening their lives."

Some armed opposition groups have also announced ceasefires as Myanmar recovers from the strongest quake with an epicentre on its landmass since 1912.

However some have continued their offensives, according to residents in combat zones.

A member of a junta-allied militia in Karen state said "armed groups could reach agreement for a ceasefire for the sake of the people" but they were being pressured to fight by pro-democracy activists.

"It's difficult to go against their pressure," he said, speaking on condition of anonymity.

Throughout the truce junta forces have been battling opposition groups for towns on a key Karen state trade route to Thailand.

"Although we haven't lost our homes like quake victims in Mandalay, we still cannot go back home because of fighting," said Phaw Awar, a resident of the besieged town of Kyondoe.

"We are afraid of air strikes," she said.