Papua New Guinea's northern island provinces and parts of the north coast have been swamped by huge waves, causing widespread destruction but no casualties.
Initial reports from New Ireland province and coastal Wewak, the capital of East Sepik province, said hundreds of homes were submerged and more than 1,500 people were displaced by the flooding.
East Sepik province was the site of the devastating Aitape tsunami in 1997, in which nearly 3,000 people died.
Local authorities from Wewak and Kavieng, the capital of New Ireland province, have sent SOS messages to the national government in Port Moresby to assist with evacuation and relief operations.
The huge waves that lasted for about six hours swamped PNG's north coast and created pools as deep as two metres, flooding homes, hotels, schools and police and army barracks with debris.
Prime Minister Sir Michael Somare's Karau village at Murik Lakes in East Sepik province was reportedly last night under water, while the two-storey Wewak residence of his son Arthur Somare, who is the Minister for State Enterprises, also had a metre of water flooding the ground floor.
The East Sepik provincial government has set up a disaster working committee comprising government officers and PNG Defence Force personnel who will travel to the affected areas and report back to the provincial disaster office on the extent of damage.
Provincial disaster coordinator Michael Kaprangi told PNG's The National newspaper that after receiving the reports, he would send a detailed report with a request for assistance to the National Disaster and Emergency Office in Port Moresby by 7pm last night.
In New Ireland, officials could not confirm the extent of the damage due to communication problems and the remoteness of some of the far-flung and outlying islands.
Provincial disaster officials said no casualties had been reported so far but they appealed for urgent relief supplies of water and food as gardens had been washed away.
Provincial Disaster Coordinator Elsie Wambun told The National that the worst-affected areas were the St Mathias Group of islands comprising the main island of Mussau, Emirau Island and Tench Island.
She said strong wind warnings were in force in the coastal areas and residents living along the waterfront have been asked through Radio New Ireland and two-way radios to move to higher ground.