The 27-year-old man who died just 200 metres from the finish line at yesterday's City2Surf was "a fit, intelligent and lovable" Briton who had been in Sydney for a few years.

Lee Marriage collapsed on the home stretch of the race, at Bondi Beach, after suffering a heart attack about 11am yesterday. Paramedics were unable to revive him.

Mr Marriage was originally from the UK, but had lived in Darlinghurst and worked at the local offices of an IT solutions company for a few years, said a friend and former colleague, Julie Nguyen.

"He was really intelligent, fit and a really lovable guy with a great sense of humour,'' she said.

"When I heard about the news I was shocked.''

Mr Marriage had a girlfriend in Sydney, she said.

Within hours of Mr Marriage's death, friends and family had posted tributes to him on his Facebook page.

His sister, Louise Marriage wrote: "My little brother, I love you so so much & cant believe they have taken you from us, how cruel, you will always be with me such a wonderful special person, so kind and caring and loved by so many! My only grace is to know how so very happy you were, you met your soul mate, the love of your life in Michelle and you were beaming with love and happiness when you were here last!''

Another friend, Shaun Lydon wrote: "Mate, what can i say im gutted more then gutted . You will always be a brother to me, you lived your dream life in oz with the person you loved and it got taken away.''

Mr Marriage also maintained a blog, in which he wrote about how to implement IT solutions.

Paramedics tried to revive Mr Marriage after he collapsed at 11am, but he was pronounced dead a short time later.

A report is being prepared for the coroner.

A witness, who was running in the race, said she saw paramedics treating Mr Marriage.

She realised he had had a heart attack when the paramedics started using the defibrillator, she said.

"I saw him lying on the ground. There were several people [treating him] and they had his shirt off and someone yelling to [runners] to keep moving - it was quite unsettling,'' she said.

"He seemed fit, he wasn't rippling with muscles but he had a slim build - he wasn't fat.''