This year's rain and storm season is expected to arrive late - and be even more unpredictable.

Low-pressure systems over the East Sea usually bring tropical storms and heavy rainfalls between May and June.

However, so far, none had been reported, said the head of the National Centre for Hydro-meteorological Forecasting, Bui Minh Tang

He said that this could mean that when they did arrive, they would be far more complicated and could lead to serious flash flooding.

"And this year's storm season is likely to last until the end of this year, just like in 1983 and 1998," Tang warned.

Large-scale flooding is now forecast for central and northern rivers from August to October and from July to November in the Central Highland region.

Tang warned people to prepare against sudden floods, storms and landslides in mountain areas.

Head of the Department for Dyke Management and Flood and Storm Prevention Tran Quang Hoai said only limited work had been done this year.

Hoai said the situation was getting worse, blaming urbanisation for encroaching on flood-drainage corridors.

He said district-level authorities were the key to improving the situation.

The vice chairman of Phu Xuyen District People's Committee in Hanoi , Nguyen Dinh Chieu, suggested local authorities be regularly updated about storms.

He also called for tighter management of dyke systems and sand exploitation along river banks.

The chairman of Thach Ha District People's Committee, Do Khoa Van, said the State should give financial support to local authorities to consolidate dyke systems - and to supply rescue equipment.

Last week, 80mm of heavy rain caused flash floods in Tuong Duong District in the central province of Nghe An. Initial losses were estimated at 10 billion VND (526 million USD)./.