A pensioner was allegedly burned alive inside a sauna in Thailand.

Exercise lover Thanchanok Petchkaew, 68, entered the steam bath after exercising at Fitness Firt at the Central Chaengwattana shopping mall in Nonthaburi, at around 11 am on June 10.

However, she collapsed on the floor from the extreme heat and was later found by shocked employees lying unconscious with her skin peeling off at around 6 pm.

Despite efforts to revive her, Thanchanok was declared dead at the scene.

Police Captain Itsarawut Nakya of the Pak Kret Police Station said: 'The deceased was an elderly woman who was a regular customer at this shop.

'The fitness staff tried to rescue her by bringing her out of the sauna room. Then, they gave first aid by performing CPR, but were unsuccessful because she no longer showed any vital signs.

'We do not believe the death was suspicious. We are now waiting for the results from the police hospital.'

He added that the prolonged heat exposure had peeled off parts of Thanchanok's skin on her arms, chest, and face, exposing the reddened flesh.

Staff said Thanchanok was a regular patron who frequently worked out at the centre on her own. Her social media profile shows that she was a gym fanatic who exercised regularly with friends.

They said that on the day of her death, she arrived at 8 am and was last seen at around 11 am. The workers assumed she had just gone home before finding her body in the sauna in the evening.

Police said they have collected evidence at the scene and informed Thanchanok's family of her death.

Her body was taken to the Central Institute of Forensic Science for a post-mortem examination.