Rising floods in Vietnam’s Mekong Delta are threatening the country’s main rice-growing area, authorities said Tuesday.

Water from heavy rains upstream in Laos and Thailand, combined with high tides in the low-lying areas of the river’s delta, are putting thousands of hectares of the newly planted crop at risk, said Phan Thanh Minh, director of the Southern Centre for Hydro-Meteorological Forecasting.

The delta’s waters were rising at a rate of 4 to 6 centimetres per day and were likely to rise to 4 metres above sea level Wednesday.

If they rise any further, Minh said, they could break dykes and flood houses in some areas and drown the rice planted in the surrounding fields.

Farmers in the Mekong Delta have planted about 600,000 hectares of rice for the year’s second crop, 100,000 hectares more than the same period last year.

Although the area is protected by dykes, some would not withstand water levels above 4.5 metres, local authorities said.

Vietnam’s Central Steering Committee for Flood Prevention and Control has ordered localities to plan to reinforce the dykes and pump water from paddy fields to protect the crops.

It has also ordered the evacuation of several thousand households in landslide-prone areas.