Nathan Baggaley, a former kayaking world champion, has pleaded guilty to manufacturing methamphetamine.

The Australian athlete, who won two silver medals at the Athens Olympics in 2004 and three gold medals in the world championships, had faced nine charges on the manufacture, import and supply of large amounts of drugs but, having admitted at a court in Sydney to conspiracy to manufacture and manufacturing a marketable quantity of meth, the other charges were withdrawn.

Baggaley has faced other drug-related charges over the past five years and in 2005 he had tested positive for a banned steroid and was suspended by the International Canoe Federation.

He was arrested on these charges in November 2013 and accused of being part of a group that set up drug laboratories in Tweed Heads, New South Wales and on the Gold Coast in Queensland – both in residential areas that led to concerns by the police for public safety. His brother Dru Baggaley also pleaded guilty to aiding and abetting and conspiracy to manufacture drugs.

Baggaley will appear in the Sydney district court on 6 March when a date for sentencing will be set.