NEW YORK (AFP) - Sam Smith, the 22-year-old singer whose incessant touring helped make him a global sensation, said on Thursday he would undergo surgery on his vocal cords and cancelled weeks of shows.

After flying to Los Angeles to see a specialist for a haemorrhage on his vocal cords, Smith said that doctors told him he needed an operation.

"I'm so gutted to be missing all the shows and events I was meant to be playing at," he wrote on Instagram.

"The doctors say I will be back in six to eight weeks and I cannot wait to sing for you all soon," he wrote.

Smith said he was told that, after the operation, "I'm gonna be able to sing like never before, so it's worth it." Smith said he would undergo the operation next week and would not be able to speak - let alone sing - for three weeks afterward.

Among his upcoming dates, he had been scheduled to sing on May 16 at the inaugural Rock In Rio USA festival in Las Vegas.

He also cancelled appearances at two major British events - the BBC Radio 1 Big Weekend in Norwich and the Capital FM Summertime Ball at London's Wembley Stadium - and June 17 and 18 shows at the Olympia in Paris.

Smith earlier called off shows in Japan, the Philippines and Australia, where doctors noticed the haemorrhage following a concert in Sydney.

Smith, who until a few years ago was a bartender in London, quickly won a global fan base with his soulful ballad about a one-night stand, Stay With Me, and maintained a punishing travel schedule.

He was the big winner at the Grammys in February, winning awards in three of the four most prestigious categories.