The Mekong river, which reached record highs in Laos in recent days, started to fall Friday in the capital Vientiane and should spare the city serious flooding, a government spokesman said.

"The water (level) has begun to drop," foreign ministry spokesman, Yong Chanthalangsy, told AFP by telephone. "Nonetheless, we are paying a lot of attention to the situation."

Large swathes of Laos have been inundated by flood waters for the past month, including Luang Prabang province -- home to the ancient royal capital of the same name that is a UNESCO World Heritage site.

The ancient capital did not suffer considerable damage, Yong Chanthalangsy said.

The situation deteriorated last weekend when powerful tropical storm Kammuri swept through the country.

The floods have killed four people and tens of thousands of hectares of rice fields have been destroyed, officials said.

The spokesman said authorities were now concerned about the water shuttling south.

"The amount of water advancing toward the south is going to make the water level rise in the centre and the south," he said.

Laos, a nation of six million, is one of the poorest countries in Southeast Asia.