NGO Save the Children says the victims of the high tides in Papua New Guinea urgently need food, clean water and shelter.
The tides engulfed many areas last week, affecting parts of Morobe, New Ireland, Manus, Bougainville, West and East Sepik, and Madang provinces.
The government estimates around 50 000 people could be affected across all provinces and one death has been reported.
Save the Children's programme director, Manish Jain, says it's assessing the situation in East Sepik, where about 6 - to 7 thousand people are affected.
Mr Jain says a few hundred people are sheltering in two care centres there.
"We may be working with these two care centres, because while they have been set up, we understand that people in there are not sufficiently supported. So we'll be responding with food, water, tarpaulins, bednets, possibly some safeplay areas for children."
Manish Jain says at least 42 houses and hundreds of food gardens have been destroyed.