Sri Lankan military doctors have removed what is now recorded as the world's largest kidney stone from a 62-year-old retired soldier, the army said Wednesday.

The stone removed from ex-sergeant Canistus Coonge weighed 801 grams (28.25 ounces), more than five times the weight of an average male kidney, the army said.

Coonge's kidney stone measured 13.37 centimetres (5.26 inches) long, compared to an average kidney which is about 10 to 12 centimetres long.

"The removal of the world's largest and heaviest kidney stone through a major surgery occurred on June 1 at the Colombo Army Hospital," the military said in a statement.

Coonge told the local Swarnavahini TV that he had abdominal pain since 2020 and oral medication had not helped.

"I was told to undergo surgery after a recent scan," he said. "I feel normal now."

The Sri Lankan case surpassed the largest kidney deposit previously recorded of 620 grams from a patient in Pakistan in 2008, according to Guinness World Records.

Officials announced the finding on Wednesday after Guinness World Records recognised it.

"The most important thing for us is that the kidney is functioning normally despite this stone," army surgeon K. Sutharshan said.

Stones are deposits made when minerals and salts crystallise in the kidney as it filters the blood.

Passing the stones can cause excruciating pain, requiring surgery if they are too big and get stuck.