Fiji has been crowned the first men's rugby sevens Olympic champions after crushing Britain 43-7 in the final of the inaugural tournament, giving the Pacific island nation its first Games medal.

In a breathtaking display of power rugby, the Fijians ran in five tries to take a 29-0 lead at half-time before taking their collective foot of the gas a little and adding only two more after the break.

Skipper Osea Kolinisau, Jerry Tuwai, Jasa Veremalua, Leone Nakarawa, Vatemo Ravouvou, Josua Tuisova and Viliame Mata all scored tries as Fiji collected its first Olympic title at its 14th Games.

Sorry, this video has expired Fiji fans go wild as country wins first gold for rugby 7s

The shell-shocked British failed to even get out of their own half in the opening period and when Dan Norton finally touched down for their only score it was only ever going to be a consolation.

Their mission complete, the Fijian players, many of them in tears, linked arms in a circle on the halfway line and sang together with eyes raised up to the dark skies above.

"They just attacked everything, they went for everything and it all paid off," said Britain's James Rodwell.

Britain's Princess Anne awards a gold medal to a member of team Fiji on his knees during the victory ceremony. ( Reuters: Alessandro Bianchi )

"That's how it goes sometimes, that's rugby sevens and they're one of the best there is.

"They've won the world series for the last two years and now they've added an Olympic gold medal so credit to them, they had an absolute blinder."

Japan's remarkable run at the tournament, which included victories over the All Blacks and France, came to an end with defeat to the Fijians in the semi-finals earlier on Thursday.

Their hopes of having a bronze medal to show for their giant-killing exploits were crushed by South Africa, who ran out 54-14 winners in the opening medal match.

They were the first men's rugby medals awarded at the Olympics since the 1924 Paris Games, where the United States won gold in the 15-a-side game.

New Zealand, who have dominated sevens for much of the last two decades but were sent out of the tournament by the Fijians in the quarter-finals on Wednesday, finished fifth.

Reuters