Myanmar is at the heart of a growing narcotics crisis in Asia that threatens public security, the UN said Wednesday, urging regional help for the impoverished nation in stemming drug production.

The long-isolated southeast Asian nation, the world's second-largest opium producer, also remains a "top source" of methamphetamine pills in the region, the UN Office on Drugs and Crime said in a report.

"During the past five years, the availability and use of methamphetamine has increased significantly," said Gary Lewis, UNODC regional representative.

Nearly 123 million methamphetamine pills were seized in the region last year -- a nine percent decrease on 2010, but a more than 500 percent jump from 2007.

"This and the increasing involvement of transnational organized criminal groups in the illicit trade of amphetamine-type stimulants (ATS) pose a growing threat to both security and public health in the region," Lewis said.

Around 5.9 million methamphetamine pills were seized in Myanmar in 2011, almost double the figure for the previous year, the report said, adding that the numbers "do not reflect the full extent of manufacture" because the drug is quickly trafficked from border regions into neighbouring countries.

Lewis told a press conference in Bangkok that "all countries in the region need to work together", because many of the chemicals needed to produce the drug are thought to be smuggled into Myanmar.

"Both on methamphetamines and poppy cultivation we need to focus our attention on Myanmar," he said, urging the region to focus on alternative development and law enforcement.

Myanmar, once the world's largest producer of illicit opium until it was replaced by Afghanistan in 1991, has seen an increase in poppy cultivation over the past six consecutive years. An estimated 17 percent more land was used for growing the drug in 2012 than in 2011.

The drugs trade is closely linked to Myanmar's long-running insurgencies in remote areas bordering Thailand and China, with ethnic minority rebels widely thought to use drug profits to fund operations.

In May the reformist government signed a deal to wipe out opium and other drug production in eastern Shan state, with a number of rebel groups currently engaged in ceasefire talks.

Lewis said production of methamphetamine in small, difficult to detect laboratories, along with distrust between the rebels and authorities means "there is a risk of continued production by groups who see that it is in their interest to hedge their bets".