Flooding, landslides and torrential rains have killed at least 23 people in Papua New Guinea's Highlands region, where homes have been damaged and roads washed away.

Acting Director for the National Disaster Centre, Lusete Man said a mother and child were among the dead as bad weather hit multiple communities.

"The 23 were buried under tons of mud in three separate landslides in different parts of Simbu province," Man said on Monday.

"We are still experiencing heavy rains, landslips, flooded rivers, that have caused extensive damages in the highlands."

The province, also known as Simbu, is made up of six districts and is home to about 376,000 people.

Coastal communities have also been hit, with rising king tides sweeping away seafronts and flooding beachside villages.

In the Gulf and Western deltas, rising waters from flooded rivers have caused havoc to communities, their food gardens and livelihoods.

The government has allocated 10,000 Papua New Guinean kinas ($2,645) for relief assistance.

Nearby Enga province has also experienced heavy flooding.

Wapenamanda community leader Aquila Kunzie told RNZ Pacific the community was rationing its food supply.

"Constant continuous rainfall in Wapenamanda district has caused rivers to flood," Kunzie said.

He added that more than 100 women and children had taken refuge in his village following nearby tribal warfare.

"[We are eating] only one meal per day, we can't afford breakfast and lunch with all of them," he said.

"We have no way to call out for help."

A New Zealand Ministry of Foreign Affairs and Trade spokesperson told AFP it had not received a request for aid.

"We will be in touch with our diplomatic post in Port Moresby for further detail, and will continue to monitor closely," the spokesperson said on Tuesday.

Papua New Guinea is ranked as the world's 16th most at-risk country to climate change and natural hazards, according to the 2022 World Risk Index.