Stewart out of Games for doping

The ban was imposed by the Sports Tribunal for attempted use of erythropoietin or EPO and for possession of human chorionic gonadotrophin (hCG).

Cycling's governing body, BikeNZ, said it felt extremely let down by Stewart's actions and fully supported the Sports Tribunal's decision and the investigation process carried out by Drug Free Sport New Zealand.

Bike NZ chief executive Kieran Turner said the organisation had "zero tolerance" towards drug use.

"We take our team culture and values very seriously as part of the overall development of our athletes," Turner said.

"We have a zero tolerance policy to anyone who waivers from this."

Stewart left New Zealand two months ago with the sprint squad, who have been training and racing in United States and Europe in preparation for the Commonwealth Games.

Once advised of the investigation, BikeNZ met with Stewart, who agreed to leave the squad immediately and return to New Zealand.

Turner said the team has cover within the sprint squad for New Delhi, but will be discussing possible options with the New Zealand Olympic Committee to add to the squad.

BikeNZ had worked extremely hard in the last three years to establish a world-class high-performance culture and discipline within the organisation, Turner said.

Part of that had involved close liaison with Drug Free Sport New Zealand, who worked with all high performance athletes with education on anti doping rules.

"There's more to being a professional athlete than just being able to ride a bike fast and we want to develop leadership and responsibility within all who represent us on the world stage," Turner said.

"Our riders have been part of developing those values and there's been a buy-in from everyone involved in our programme.

"Adam Stewart knows what he has done has clearly broken that trust."

He said Stewart had let down BikeNZ board, staff, stakeholders, coaches and his team-mates.

"This is a young man who has made a very silly mistake and he therefore must pay the consequences of his actions."

Stewart competed at the 2006 Melbourne Commonwealth Games, finishing 14th in the individual sprint as well as being part of the men's sprint team that finished fourth.