A natural gas station in Ghana's capital Accra exploded yesterday evening, killing an unknown number of people, a government official said.

"Unfortunately there are some fatalities and we are working to have the numbers," Deputy Information Minister Kojo Oppong Nkrumah told a local radio station. "There are quite a number also injured."

He added that the main blaze was largely under control and that the government planned to release casaulty figures this morning.

Several eyewitnesses told Reuters they had counted four or five bodies, although some bodies could have already been removed from the scene.

The explosion at around 7.30pm local time (1930 GMT) began at a state-owned GOIL liquefied natural gas station and spread to a Total petrol station across the street at the city's Atomic Junction, a Reuters witness said.

Frightened residents ran from the explosion, which sent a giant fireball high into the sky above the city, and several fire trucks and ambulances were deployed to the scene.

People ran for their life after the fireball engulfed the evening sky. Photos: Reuters

An explosion at a petrol station in Accra in 2015 killed around 100 who had sought shelter nearby from flooding in the country's worst disaster in more than a decade.

Infrastructure in Accra, a city of roughly 7 million people, has failed to keep pace with population growth after years of rapid economic expansion.

A small unit on a tower building at Ghana's Parliament also caught fire in July, although the blaze did not cause major damage.