Tributes have been pouring in after the death of a World Champion swimmer from Norway, who was tipped to win gold at the London 2012 Olympics.

Alexander Dale Oen was with team mates at an altitude training camp in Arizona, when a colleague found him collapsed in the shower room on Monday night just 2 days before they were due to leave for home. Doctors suspect he died of a sudden cardiac arrest. He was just 26 years old.

A medal winner of epic proportions, Oen's prowess in the swimming world was undisputed. 100 Metres Breaststroke champion last year, the country's first Gold Olympic Medal in the sport at Beijing in 2008 and he was the first ever Norwegian man to win Bronze at the 2006 Short Course Championships.

Flags flew at half-mast at the Norwegian Swimming Federation HQ and its President Rune Eknes described Oen.

National Swimming Coach Petter Loevberg said everyone will miss him.

It's clear the people of Norway will grieve for Oen and afford him the same respect as the swimmer himself did just 3 days after the massacre of 77 people by Anders Breivik. Oen dedicated his winning 100 Metres Breaststroke final swim to the triumph of his fellow countrymen.