Tasker was Executive Director of New South Wales Swimming from 1990 to 1998. During this appointment, he played a significant role in introducing events for swimmers with disabilities into the NSW Age Swimming Championships, a first for any Australian state swimming championship. From 1998 to 2000, he was Swimming Competition Manager at the Sydney 2000 Olympic and Paralympic Games. In 1999, he was the Event Manager of 1999 Pan Pacific Swimming Championships. After the Sydney Games, he was General Manager of the NSW Amateur Soccer Association. In 2001, he was appointed to Chief Executive Officer (CEO) of Swimming Australia, a position that he held until June 2008. Tasker took up the position when Swimming Australia was undertaking a period of major change with long standing national coach Don Talbot and executive director Vena Murray leaving the organisation. During his leadership at Swimming Australia, Australia had its most successful Olympics for the sport of swimming at the 2004 Athens Olympics since the 1956 Melbourne Olympics, winning seven gold medals. It also won five gold medals at the 2008 Beijing Olympics. Issues which Tasker managed whilst CEO included the leaking of Ian Thorpe's abnormal doping violation, Ian Thorpe's disqualification from the 400m Freestyle at the Olympic trials after a false start and Nick D'Arcy removal from the Australian team at the 2008 Beijing Olympics after assaulting Simon Cowley.