The area under opium poppy cultivation in Myanmar has shrunk by a quarter in the last two years, a UN study said Wednesday, as demand for opiates eases and methamphetamine use surges.

Myanmar remains the world's second largest producer of opium -- the base ingredient for heroin -- and is at the heart of methamphetamine production in Southeast Asia.

But this year 41,000 hectares (101,313 acres) of land were being used to grow poppies -- whose seeds are refined into opium paste -- down from 55,000 in 2015, according to estimates by the United Nations Office on Drugs and Crime (UNODC).

The downward trend comes with "declining opium prices and anecdotal evidence of reduced trafficking", said the UN's annual Myanmar Opium Survey, using the latest period of comparable data.

Myanmar's drug production is centred on the conflict-riddled border areas of Shan and Kachin states.

Simmering ethnic rebellions, lawlessness and porous frontiers allow industrial-scale businesses in heroin, pills and ice -- crystal methamphetamine -- to flourish.

"The connection between governance and security on the one hand and poverty and conflict on the other is undeniable," the UNODC's Jeremy Douglas said in a statement.

Poppy cultivation declined most sharply in east Shan state, the study said, where it dropped by an estimated 37 percent.

In the heyday of the "Golden Triangle" in the 1970s and 1980s, Myanmar was the world's top opium producer -- a designation it lost to the Afghan farmers who now dominate the market.

But Myanmar's border areas are at the heart of the Asia's methamphetamine production, with warlords pumping out record numbers of caffeine-laced "yaba" meth pills and the more addictive crystallised version called "ice".

In the statement, Myanmar's Home Affairs Minister General Kyaw Swe, acknowledged "there is still much to do" to provide farmers with alternative incomes to opium, as well as curbing production of other drugs and cracking down on precursor chemicals that flood into the country.

Police in Myanmar and Thailand routinely trumpet their multi-million-dollar hauls of ice and yaba.

But they have struggled to dismantle the sprawling drug networks that funnel Myanmar-made narcotics through the region, or catch the shadowy heads of the drug networks.