Papua New Guinea volcano has erupted forcing evacuation of locals.

Qantas has been forced to alter international flights out of Sydney as the volcanic eruption spews ash into the air over Papua New Guinea.

Qantas flights between Sydney and Shanghai and Sydney and Narita have been rerouted. Flights QF21, QF22 and QF130 will fly over central PNG in order to avoid the ash cloud over Rabaul.

According to a Qantas spokesperson, the new flight paths will not have an effect on the flight timings.

Mount Tavurvur volcano has erupted in eastern Papa New Guinea, emitting ash and rocks into the air and forcing the evacuation of local communities.

The volcano, which devastated the town of Rabaul when it exploded simultaneously with nearby Mount Vulcan in 1994, rumbled to life on the tip of the island of New Britain.