Authorities have evacuated hundreds of people after a volcano erupted beside a glacier in southern Iceland, but there were no immediate reports of damage or injuries.

The eruption occurred around 11.30pm yesterday, beside the Eyjafjallajokull glacier, the fifth largest in Iceland.

Authorities initially said the eruption was below the glacier, triggering fears that it could lead to flooding from ice melting, but scientists conducting an aerial survey today located the eruption and said it did not occur below the ice level.

"The eruption is a small one," said Agust Gunnar Gylfason, a risk analyst at the civil protection department. "An eruption in and close to this glacier can be dangerous due to possible flooding if the fissure forms under the glacier. That is why we initiated our disaster response plan."

Scientists can see lava flows in the half-mile long fissure, and are watching for further activity.