A magnitude 6.6 earthquake has struck Papua New Guinea's north in a region where a huge tsunami killed more than 2,000 people in 1998, with reports suggesting the area escaped serious damage.
The quake, at a depth of just 13km, hit 23km east of the small town of Aitape, with a population of around 8,000 on the Pacific nation's north coast on Wednesday, the US Geological Survey said.
"We are aware of the earthquake off Aitape in Papua New Guinea. There have been no reports of serious damage or injury," a spokesperson from Australia's foreign office told the AFP news agency.
No destructive tsunami warning was issued by the Pacific Tsunami Warning Center but it cautioned that earthquakes of this size could sometimes generate local tsunami waves.
A giant tsunami in 1998 smashed into the coastline around Aitape following an off-shore earthquake that triggered waves measuring up to 10 metres, which swept away churches, schools and other buildings.
Phone lines to Aitape appeared to be down but the PNG National Disaster Centre said it had been in touch with officials in the town of Vanimo some 150kms away and no tsunami waves had been seen.
"If there was going to be a tsunami it would have been there by now," Chris McKee from the disaster office said.
Geoscience Australia said around 60,000 people would be in the exposure zone.
"There is the possibility of considerable damage. It certainly could bring buildings down," seismologist Steve Tatham said.
"This would include outlying local villages," he said, adding that there would have been "a high level of shaking".
Police, ambulance and church officials in Aitape could not be reached but the PNG National Broadcasting Corporation said it had spoken to community leader Paul Reptario in the town.
"He says his whole house was shaking while his vehicle almost overturned," the broadcaster said.
"He ran down to the beach to check for signs of tsunami like receding waves but there was none. Reptario said houses and other infrastructure in his village were not damaged," it added.
The Australian Broadcasting Corporation also cited an Aitape local as saying there had been no unusual waves and no significant damage, but said that people had panicked.
"They were all running around the street. They were frightened maybe the sea will come up," said Max Kamave from the Aitape Resort Hotel.
Personnel at Wewak Hospital, about 150kms from the coastal epicentre, said they too felt the tremor but there was no immediate reports of damage from their town.
"It was a strong one. This is a solid building - not iron but solid - and it was shaking," hospital spokesman Morris Iuandu said.
He estimated that the swaying had lasted at least three minutes. Wewak resident Gregory Moses described it as a "huge earthquake".
"Everything literally was shaking and I thought the roof was going to cave in any minute but thank God it’s now over," he said on Facebook.
Quakes of such magnitude are common in impoverished PNG, which sits on the so-called Pacific "Ring of Fire", a hotspot for seismic activity due to friction between tectonic plates.
A 6.6-magnitude quake struck the country's Bougainville Island on Sunday, but there were no reports of damage or injuries.