Opposition politicians in Guatemala want the head of the emergency response agency (Conred) to be dismissed.
They say Conred failed to heed advance warnings about Sunday’s deadly eruption of the Fuego volcano.
A senior opposition figure, Mario Taracena, said the government should investigate whether there was criminal negligence.
Ninety-nine people are now known to have died since Sunday, and nearly 200 others remain unaccounted for.
Villages on the slopes were buried in volcanic ash and mud after Fuego erupted.
Subsequent smaller eruptions and the high temperatures of the rock and mud debris have made search teams’ work extremely difficult.
More than 1.7 million people have been affected, with more than 3,000 evacuated.
What is the emergency agency accused of?
Analysis by the BBC’s Will Grant in Guatemala
The argument revolves around a crucial question: was the order to evacuate given clearly and with sufficient warning before Volcan de Fuego erupted on Sunday?
The national institute for seismology and volcanology says that its conscience is clear, that it issued the relevant warning in plenty of time.
It claims the responsibility for any failings lies with the civil emergency authority, Conred, which didn’t then act on its warnings.
It has been shown that Conred’s Twitter feed as late as 11:00 on the morning of the eruption said that it wasn’t yet necessary to evacuate.
The organisation has denied it was to blame and that when it did issue the alerts, they were ignored.