Hagupit made landfall in Vietnam on Wednesday, triggering severe flooding and landslides in eight mountainous provinces, said the national flood and storm control committee.

Deaths were reported in five provinces, the committee said on its website. Several thousand homes have suffered flood damage.

Prime Minister Nguyen Tan Dung on Saturday asked relevant authorities to mobilise all resources to rescue those stranded by floodwaters and closely monitor the country's river dyke system, as water levels remain high.

Rescue workers and soldiers have reached some flood-hit areas by boat, distributing instant noodles, clean water and medicine to those in need, the Hanoi-based committee said.

Weather forecasters have said a tropical storm forming in the South China Sea could affect Vietnam over the next few days.

Floods and storms in Vietnam claim hundreds of lives every year between July and November.