Myanmar's junta announced a temporary ceasefire on Wednesday as the death toll from a devastating earthquake rose and desperate survivors pleaded for more help amid frantic scenes of aid distribution.

The shallow 7.7-magnitude earthquake on Friday flattened buildings across Myanmar, killing nearly 3,000 people and making thousands more homeless.

The military government said it would observe a ceasefire from Wednesday until April 22 to make quake relief efforts easier, after other armed groups fighting the country's bloody four-year civil war made similar pledges.

Rights groups and several foreign governments had earlier condemned the junta for continuing to carry out air strikes even as the country grappled with the quake aftermath.

The junta said in a statement the ceasefire had "the aim of speeding up relief and reconstruction efforts, and maintaining peace and stability".

But it warned its opponents - a complex array of pro-democracy and ethnic minority armed groups - it would still respond to attacks, acts of sabotage or "gathering, organising, and expanding territory that would undermine peace".

The junta also said leader Min Aung Hlaing will travel to Bangkok on Thursday for a summit of South Asian countries plus Myanmar and Thailand, where he will discuss the quake response. (AFP)