Known as the "Paekakariki Express" Cullen was considered to be one of the most potent running fullbacks rugby has ever seen. With 46 tries scored in 58 Tests, Cullen is the 9th-highest try-scorer in international rugby.Read more exclusive columns
Cullen sees challenges for Sevens Olympians
30 Jan 2016 Getty Images
"Getting to score 18 tries in a tournament as prestigious as Hong Kong was an honour for me and it was amazing to get involved in such a great team. That final against Fiji was something else, a real battle and a great occasion for all of us," he told Worldrugby.org.
He went on to experience winning a Commonwealth Games gold medal in 1998 with New Zealand and having played at such a major sports festival he believes the Olympic Games in Rio de Janiero will have some challenges, especially for those players still new to Sevens.
The fact that there will be two matches per day for three days should suit newcomers.
"The tournaments we used to play in you could end up playing six games in two days if you reached the final which is tough for the guys involved.
"The three-day format you can manage your injuries better, your recovery better," he said.
"The Olympics will be interesting, two games in a day, you can almost just bang it out. You have your first game in the morning then have that rest. You will still need the fitness and as Gordon Tietjens has said already, these 15s guys need tournaments.
"The boys are almost the same body shape as each other now, all of them are serious athletes. Back in the day there were all types of body shapes. Now the forwards are as fast as the backs.
"Guys like Sonny Bill [Williams], ball in hand will be awesome, but defensively it will be a big challenge. One on one with a light guy, lightning step, will be hard for anyone coming into it," Cullen said.
He was looking forward to seeing how the XVs players make the adjustment in the Wellington tournament.
While admitting he missed playing the game, Cullen said he didn't miss the training.
"I miss the game no question, but now I watch them play I am happy I am retired," he said.