COLOMBO (AFP) - Sri Lankan customs on Wednesday seized 2kg of gold from two men who had hidden the precious metal inside their bodies in an attempt to smuggle it out of the country, an official said.

The two Sri Lankans were caught just before they boarded a flight to the Indian city of Mumbai, customs spokesman Leslie Gamini said, adding that it was the biggest haul of gold they had found inside a person.

"Each man had 10 gold biscuits weighing 100g inside his rectum," Mr Gamini told AFP. "They were easily spotted because they appeared to be in pain and could not walk properly."

He said the gold, valued at nearly US$100,000 (S$125,000), was confiscated and the men were fined US$384 each.

He added that customs officials at Sri Lanka's main international airport had stepped up vigilance over the smuggling of gold to India after New Delhi raised import duties.

India, the world's biggest buyer of gold, raised duties last month on bullion imports for the third time this year as it battled to narrow a record trade gap and stabilise the rupee.

Mr Gamini said seven Indian-bound passengers were arrested on Monday when X-rays showed 25 "metal objects" inside their stomachs.

"They include six Indian nationals and one Sri Lankan," Mr Gamini said. "Two of them have passed four pieces of gold after being given laxatives. Others are still under observation."