A volcano in Indonesia's northern Sumatra province has erupted, sending volcanic ash 4km into the sky.

Photo: AFP / Lana Priatna / NurPhoto

Mount Sinabung's eruption occurred at 3.36pm local time on Wednesday, a national disaster management agency spokesperson told media.

Footage posted online by the Indonesia volcano monitoring programme MAGMA showed volcanic ash from Mt Sinabung down to street level in a village.

Abu vulkanik dari erupsi Gunung Sinabung turun ke permukaan dengan air hujan. Lokasi di Berastagi. Selalu siap dengan segala situasi, siapkan masker untuk melindungi pernafasan dan jas hujan maupun payung untuk melindungi diri dari hujan bercampur abu yang bersifat asam. pic.twitter.com/nwvVKIuzmn — MAGMA Indonesia (@id_magma) December 27, 2017

Volcanic ash has fallen around villages near the eruption but there had not been any casualties, the spokesman said.

The aviation code remains at 'orange' alert, one below the highest level.

Last month, the Mount Agung eruption - which has been going on since November - led to the evacuation of residents in Bali and stranded hundreds of Australian tourists.