The King of Tonga George Tupou V died yesterday in a Hong Kong hospital, Matangi Tonga Online reported last night.
However there was no immediate confirmation from Tongan authorities.
"It was (in) Hong Kong, and the Crown Prince Tupouto'a Lavaka was there at the hospital just before the king passed away," the brief report said.
"This news is yet to be officially confirmed but our reliable source informed us that the king was rushed to hospital early this afternoon but it is understood that he had passed away a few hours later."
Government and royal palace officials in Tonga were not immediately available to comment on the report that the 63-year-old monarch had died. The next in line to the throne is Crown Prince Tupouto'a-Lavaka, the high commissioner to Canberra.
Tupou V, a strong advocate for democratic reform in the tiny South Pacific kingdom, was sworn in as king in September 2006 following the death of his father king Taufa'ahau Tupou IV.
However, his coronation was delayed until 2008 as the impoverished Polynesian nation of 115,000 reeled from the impact of riots in the capital Nuku'alofa.
Eight people were killed and much of the central business district was destroyed in the November 2006 riots when people protested against the slow pace of political reform.
Within two years after his coronation, Tupou V made good on his pledge for democracy and the people of Tonga were able to vote in their first popularly elected parliament.
The democratic changes replaced the former feudal system where the kingdom was run by a parliament dominated by a clique of nobles selected by the king, who also chose the prime minister and cabinet.
Outside Tonga, the king was known for the elaborate uniforms, colonial-era pith helmets, and monocles that he wore and for being driven around the capital in a London cab.
The king, who was not married, went to primary school in Switzerland and went on to study at Oxford University and the Royal Military Academy Sandhurst in England.
AFP
, the king of Tonga, has died after ten days in intensive care in a Hong Kong hospital. The 63-year-old brought democracy to his nation of 115,000 people.

The reformist swore into power in 2006 but his coronation was pushed back two years in the wake of  rioting. Eight died in violence stirred up in response to perceived inadequacy in the pace of reforms. 
The King opted to be driven around in a London taxi.
After another two years he made good on a promise to end feudal rule after 165 years, introducing a democratically elected parliament in 2010. Although the public chose nine representatives, he appointed the rest of the 33 that formed the parliament. He also picked the cabinet.

Thousands attended his 2008 coronation, including foreign leaders and hundreds of nobles. Outside his nation of islands, he was known as an eccentric who wore monocles and s, was chauffeured in a , and used model sailboats on his swimming pool.

King Tupou V has twice undergone surgery in the last year, once to remove a kidney and once to undergo a liver transplant. Unmarried, his younger brother Crown Prince  is next in line to the throne. Crown Prince Lavaka was at the King's bedside when he died.