Rescue officials have found the body of a female in the forest surrounding a Malaysian nature resort where a 15-year-old London teenager was reported missing more than a week ago.

Key points: Police have begun a criminal investigation into the girl's death

Police have begun a criminal investigation into the girl's death Ms Quoirin's family had said she was disabled and unlikely to wander off alone

Ms Quoirin's family had said she was disabled and unlikely to wander off alone Nearly 350 people were involved in the search operation to find her

Malaysian police said they were certain the body found is that of Irish teenager Nora Anne Quoirin, who went missing from a jungle resort, but were waiting for her family to make the final identification.

"We are very certain," said Mazlan Mansor, Malaysia's deputy police chief, when asked if police were sure the body was that of the missing girl.

"But we wait (until) tonight when the family visits the hospital."

The unclothed body was found near a stream about 2.5 kilometres from the resort, and was winched up and then flown by helicopter to a nearby hospital, he added.

Authorities had begun a criminal investigation into the disappearance, he said, although an initial investigation revealed no evidence of criminal behaviour.

The Lucie Blackman trust, a charity that helps the families of Britons who are in crisis overseas, said in a statement: "At this time we cannot confirm it is Nora. However it sadly seems likely."

Ms Quoirin's family had arrived in Malaysia on August 3 for a two-week stay at the Dusun eco-retreat, a small resort located in a durian orchard next to a forest reserve 63 kilometres south of Kuala Lumpur.

The teenager, who has learning and physical disabilities, was reported missing by her family on August 4.

Following the missing persons report, police said they believed the teen climbed out through an open window in the living room of the resort cottage.

The search team has involved sniffer dogs, elite forces and thermal detectors. ( Reuters: Lim Huey Teng )

The teenager's family said she is not independent, would not wander off alone, and was likely to have been abducted.

Nearly 350 people have been involved in a massive search operation including sniffer dogs, elite commando forces and thermal detectors, but no evidence had turned up until the discovery of a body on Tuesday.

Police from Ireland, France and the UK were also on site to assist in the investigation.

On Monday, the mother, Meabh Quoirin, announced a 50,000 ringgit ($17,612) reward, donated by a Belfast-based business, for information that could directly help police find her daughter.

The discovery of a body in the forest comes days after Malaysian rescuers stepped up the search to find the 15-year-old by playing voice recordings of her mother as they combed the hilly forest terrain of the resort.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 32 seconds 32 s Malaysian rescuers play mother's voice on loudspeaker to look for missing British teen

AP/Reuters