The blast occurred on Thursday in Apiate between the towns of Bogoso and Bawdie. The explosion site is about 140km from the Chirano gold mine, run by Toronto-based Kinross. The truck carrying explosives was owned by a company called Maxam.
Hundreds of buildings were destroyed, according to an official at the National Disaster Management Organisation. Unverified images on social media showed a large, smouldering crater at the epicentre of the blast.
The Ministry of Lands and Natural Resources is investigating what caused the incident and whether regulations covering transportation of explosives were complied with, it said in a statement.
Relief efforts are underway for stranded community members and people in critical condition are being evacuated to medical facilities in the capital Accra, said the information minister.