President Jacob Zuma sent his condolences to Ghana following an explosion at a petrol station in the country's capital, Accra, which killed at least 150 people.

"Our thoughts are with the people of Ghana in the aftermath of the catastrophic explosion and the torrential rain that overwhelmed and devastated the people of Ghana," Zuma said in a statement on Saturday.

"On behalf of the government and people of South Africa, I send my deepest condolences to the government of Ghana and to everyone affected, particularly to the families and friends of those killed and injured in the unprecedented explosion in the petrol station."

The department of international relations said the South Africa High Commission in Accra was in contact with authorities in Ghana and on standby to assist if there are any South Africans identified.

Many of those killed in the explosion on Wednesday night were reportedly at the petrol station seeking shelter from torrential rain.

The explosion was caused by a fire that erupted at a nearby lorry terminal then spread to the petrol station and other buildings, Reuters reported.

On Friday, authorities were clearing the wreckage. The country was reportedly bracing itself for more heavy rains.