Sri Lankan President Maithripala Sirisena's youngest brother died on Saturday in a hospital after being attacked by a man wielding an axe two days earlier, police said.

"Priyantha Sirisena died this (Saturday) morning in the hospital," police spokesman Ruwan Gnasekera said.

Sirisena, 40, a businessman, was attacked owing to a personal dispute on Thursday night in his hometown of Polonnaruwa, 215 kilometres north-east of the capital Colombo. He was airlifted to Colombo from Polonnaruwa on same night.

He was under intensive care for severe head injuries. His death came as the president was in China on a state visit.

The attacker, a friend of the deceased, has been arrested and remanded till April 8, police said.

Image: Sri Lankan President Maithripala Sirisena