An Australian tourist was rescued after injuring herself while trekking through hillsides in southern Thailand.

The holidaymaker, 59, slipped on a rock and sprained her left ankle at the Hin Lad waterfalls on Koh Samui island, Surat Thani province, on March 24.

Unable to walk, she and her Aussie boyfriend called rescue services for assistance.

Volunteers hiked through the woods and found the woman sitting on the ground. She was carried to safety on a stretcher.

The couple said they had travelled to the holiday island and had chosen to see the waterfalls that day. They added that the path was rocky and uneven, causing the female tourist to injure herself.

Rescuers applied a splint on the woman's ankle before carrying her down the hills on a stretcher.

She was taken to the Koh Samui Hospital for further treatment.