More than 20 people are missing after a military helicopter in Laos came down in poor weather earlier this week, state media said on Wednesday.

The Ministry of National Defence said the accident occurred shortly after 1 pm (0600 GMT) on Monday as the chopper travelled towards the northeastern provinces of Xiangkhouang and Houaphanh, the official Lao news agency KPL reported.

"The helicopter lost communication with Aviation Control Centre a short time after it left Vientiane Capital with 4 crew members and 19 passengers on board," the report said.

Rescuers have been sent to conduct a ground search while an aerial search was called off because of bad weather conditions, it added.

The Laos Ministry of Foreign Affairs has yet to respond to an AFP request for comment.

Laos has a history of poor air safety with both the civilian and military sectors experiencing recent deadly crashes.

In October 2013 a civilian plane operated by Lao Airlines plunged into the Mekong River in bad weather, killing all 49 people on board.

Last May a military plane crashed while also making its way to Xiangkhouang province, killing five senior officials on board including the country's defence minister.

Since the 1950s Laos has had 32 fatal air accidents, according to the Aviation Safety Network.