Three people reported dead, 1000 homes destroyed after ...

A magnitude-6.9 earthquake has destroyed an estimated 1,000 homes in Papua New Guinea after striking East Sepik province, and there are reports three people have died.

The quake hit at about 6:20am on Sunday, 38 kilometres from the town of Ambunti at a depth of about 40 kilometres, shaking villages along the Sepik River and in surrounding areas.

Papua New Guinea's Post-Courier newspaper is reporting three people died as the earthquake sent homes underwater in areas inundated by recent flooding.

A magnitude-6.9 earthquake struck East Sepik province after flooding had already inundated the region. (Supplied: Office of Member for Ambunti-Drekikir District)

East Sepik province Governor Allan Bird told the ABC regional authorities made an initial estimate that the earthquake destroyed 1,000 homes.

He said it damaged most parts of the province, which was already under strain from flooding.

"The flooding actually covers an area more than 800 kilometres long, and so there's about maybe 60 or 70 villages involved all along the Sepik River," he said.

Authorities were ready to respond to flooding this week and had medical teams on stand-by when the earthquake struck and destroyed hundreds of homes, Mr Bird said.

"The floods weren't their biggest problem. They were confidently dealing with that because it's something they're used to," he said.

"It was the earthquake that no-one was prepared for. That would have caused the most significant damage now."

Villages in East Sepik province were flooded before Sunday's earthquake.(Supplied: Cyril Tara)

Mr Bird said the most urgent needs in the disaster-affected areas were shelter and clean water, as well as canvases to keep belongings and firewood dry.

People in the quake-stricken zone reported homes being thrown under water, and said communities now faced shortages of food and clean drinking water.

Gideon Marlow, who is volunteering to assist earthquake-hit villages, said people were shocked to see their homes destroyed in the disaster.

"They were trying to help themselves, looking for ways to a safer place to move from the high flood area to the safer side," he said.

"At this moment, you know, it's a double disaster for them. So people are looking for help trying to get some sort of assistance."

Mr Marlow said in one village he visited, seven houses had collapsed while others were on the verge of collapsing.

"I'm trying to move around as a volunteer, trying to help them. It's everyone's business to help one another," he said.

Houses either collapsed into floodwaters or were on the verge of falling after an earthquake in Papua New Guinea on Sunday.(Supplied: Gideon Marlow)

A community leader in Kamanibit village in Angoram District, Cyril Tara, said 39 houses belonging to his community were under water following the quake.

He was grateful no-one in his community was severely injured or killed, but he said food including sago — a starch made from the material in the trunks of palms — was short.

"The families in our communities who were lucky to have bigger homes were able to cater for the families who had lost their homes and their belongings," he said.

"All our food gardens have been destroyed. We have fish but right now we do not have any sago following the disaster on Sunday.

"At the moment, our drinking water has also been contaminated and it's not really good, with lots of bubbles following the quake and the taste is not like what we had before."

He called on authorities, including heads of districts and Mr Bird, to visit the affected areas and see the impacts of the earthquake.

Heavy rainfall combined with strong winds have brought significant flooding and triggered landslides in Papua New Guinea this month.

Local media reported 23 people died in Chimbu province in three landslides on March 18. Storm surges have also inundated the coastal village of Lese Kavora in Gulf province.