At least 40 people have died following the explosion of a gas tanker in north-central Liberia, the West African country's chief medical officer, Francis Kateh, said on Wednesday.

The fuel truck crashed late on Tuesday in Totota, Lower Bong County, and soon after exploded, killing and injuring many who had flocked to the scene.

Dozens of people are still in hospital with serious burns, and the death toll could rise, Kateh told reporters.

Poor road safety and weak infrastructure have made Sub-Saharan Africa the world's deadliest region for crashes, with the fatality rate three times higher than the European average, according to United Nations figures.