Volvo Ocean Race officials have confirmed that missing sailor John Fisher is "presumed to have been lost at sea", after falling overboard early this morning.

Fisher, 47, an experienced big boat sailor who was sailing in his first Volvo Ocean Race, was reported overboard from Team Sun Hung Kai/Scallywag's 65-foot sloop in the early hours of Tuesday morning.

After an exhaustive search failed to find Fisher, Ocean Race president Richard Brisius has confirmed that the sailor is presumed to have been lost at sea.

"Given the cold water temperature and the extreme sea state, along with the time that has now passed since he went overboard, we must now presume that John has been lost at sea," said Brisius.

"All of us here at the Volvo Ocean Race organisation send our heartfelt condolences out to John's family, his friends and his teammates and we will do everything in our power to support them in this very difficult time."

A Maritime Rescue ship was sent to assist in the search for Fisher, but is still over a day away due to rough weather conditions.

With the rest of the Volvo Ocean Race fleet approximately 200 miles downwind, sending them back upwind to assist, against gale to storm force winds, was not a viable option, noted Brisius.

The Sun Hung Kai/Scallywag team conducted an exhaustive search for several hours in extremely challenging weather conditions, but they were unable to recover their teammate.

Team owner Lee Seng Huang paid tribute to Fisher.

"Over our long passages, I have come to know Fish well. Despite the dangers of the sport he loved his sailing. He is one of our own, a long-standing member of the team. He is a great and experienced sailor, the finest human being and a true Scallywag.

"Our thoughts and prayers are with John's family and the crew at this most difficult time, and we are working with Volvo Ocean Race to provide all the support we can. Our focus now, is getting the boat and crew to a safe harbour."

Fisher was a veteran of the Sydney-Hobart, one of the world's top, and toughest, offshore races, the team's website said.

Earlier in the race, Scallywag crewman Alex Gough fell overboard during a sail change and was rescued within seven minutes.

This edition of the classic round-the world race already had been tarnished by a collision involving Vestas 11th Hour Racing and a fishing boat that killed a fisherman.

Experienced sailor John Fisher is still missing. Photo / Volvo Ocean Race

The collision sank the fishing boat and caused severe damage to the racing yacht, forcing it to miss the next two legs.

The teams are on Leg 7 from Auckland to Itajai, Brazil. It will cover 7,600 nautical miles.

The entire race will cover some 45,000 nautical miles.

In May 2006, Dutch sailor Hans Horrevoets was swept overboard when a wave hit ABN AMRO TWO in the Atlantic Ocean.

The crew turned back and found Horrevoets but could not revive him.