Iceland's authorities have raised the aviation warning code for a region close to the subglacial Bardarbunga volcano after a small fissure eruption in the area.

The country's meteorological agency described the eruption in the Holuhraun lava field, about 5km north of the vast Dyngjujoekull glacier, as a "very calm lava eruption and can hardly be seen on seismometers".

This morning's eruption was the third eruption in the area since August 23.

On Friday, a smaller eruption also prompted authorities to briefly raise the aviation warning code to restrict flights around the eruption site.

The Civil Protection Department said all airports remained open.