BANGKOK - Opium cultivation is back on the rise in Myanmar and Laos despite government eradication campaigns, with impoverished farmers lured by higher prices and strong demand from neighbouring countries, a UN report said on Thursday.

Land used for growing opium, a paste from poppy used to make heroin, has increased by 14 percent in Myanmar from last year and 38 percent in Laos, according to satellite and helicopter surveys carried out jointly by the United Nations Office on Drugs and Crime (UNODC) and the Myanmar and Lao governments.

The two countries form part of Southeast Asia's infamous Golden Triangle, which once accounted for more than 70 percent of the world's supply of heroin.  

Myanmar accounts for 91 percent of regional production and an estimated 9 percent of global output. Afghanistan supplies at least three-quarters of global production.

Poverty and food security were a big concern in all the areas of Myanmar surveyed, with an estimated 35 percent of people having insufficient food, providing little incentive for farmers to stop growing poppies.

Cultivation in Southeast Asia climbed 16 percent in 2011 and there was twice as much land growing opium as five years ago, the survey said.

"There needs to be recognition that the lack of security, political stability and sustainable development are some of the key drivers behind increased opium production," Yuri Fedotov, UNODC executive director, said in the report.

Cultivation rose for a fifth consecutive year in Myanmar after six years of decline. The survey showed 43,600 hectares (107,700 acres) of land was used for opium, up 14 percent from 2010. Although average yields had fallen 8 percent, the larger area under cultivation resulted in an overall increase.