A volcano erupted Friday in eastern Papua New Guinea, spewing rocks and ash into the air, forcing the evacuation of local communities and international flights to be re-routed, officials said.

Mount Tavurvur, which destroyed the town of Rabaul when it erupted simultaneously with nearby Mount Vulcan in 1994, rumbled to life early in the morning on the tip of the remote island of New Britain.

"The eruption started slow and slowly developed in a Strombolian (low level) eruption with incandescent projections accompanied by explosion noises and ongoing loud roaring and rumbling noises," the Rabaul Volcanological Observatory said.

The Australian government issued a warning against travelling to the area, while flag carrier Qantas re-routed some flights to avoid the ash cloud.

"Authorities have evacuated communities close to the volcano. Residents of Rabaul town have been advised to remain indoors to avoid falling ash," Canberra said.

There were no immediate reports of injuries or damage.

The Volcanic Ash Advisory Centre in the northern Australian city of Darwin said the ash cloud was drifting southeast.

"The eruption was to 60,000 feet (18,000 metres), which is flight level. There was two hours of high-level eruption," an official from the centre, Cyndee Seals, told AFP.

"The ash was initially blowing to the southwest but has now turned to the southeast and we expect it to clip the edge of Australian airspace later today, but we don't expect ash over Australia."

She said planes may be forced to take alternative routes, with the ash forecast to move towards the Solomon Islands and then Vanuatu in the Pacific.

Qantas said three flights had been diverted.

"Flight paths between Sydney and (Tokyo) Narita, and Sydney and Shanghai have been altered as a result of the volcanic ash cloud over Rabaul in eastern Papua New Guinea," a spokeswoman said.

"QF21, QF22 and QF130 will now fly over central Papua New Guinea to avoid the cloud."

She added that it would only add 10 or so minutes to the journey.

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- Layer of ash -

In Rabaul, the ground was covered in a layer of ash, local reports said.

"Police have cautioned people not to panic but remain indoors and listen to local Radio East New Britain for updates," the PNGloop website said.

"The situation has eased except for the rumbling and roaring as rocks are shot into the air."

Rabaul International Hotel operations manager Rodney Aua said police were out in force to prevent any looting as businesses closed their doors.

"In Rabaul some people have closed their businesses and are moving to areas as far away as possible," he told AFP.

"The police are there to make sure looting doesn't happen again, like in 1994."

The 688-metre (2,270-foot) volcano has erupted several times before, notably 20 years ago.

In 1994, major eruptions at both Tavurvur and nearby Mount Vulcan destroyed much of Rabaul, with falling ash causing buildings to collapse, and while loss of life was minimal due to a quick evacuation, looters ransacked the town.

Despite the volcano continuing to rumble, Aua said the hotel still had 50 percent occupancy and for locals it was just another day in PNG, which sits on the Pacific "Ring of Fire" and where high volcanic and seismic activity is the norm.

"The situation is pretty calm," he said. "For locals most of us have grown up here and this is normal, although we haven't seen this sort of activity for a while."