He achieved outstanding international results in Great Britain, including numerous world championship, European and Commonwealth titles, although Olympic success did not come until Beijing 2008.
He has established a successful consultancy and continues to lecture, publish and conduct clinics on a variety of subjects and has produced a series of educational and instructional videos on skills and technique. He is a published author of Championship Swim Training.
"We are absolutely delighted that Bill has taken up the role with us," Swimming NZ acting chief executive Mark O'Connor said. "It is an important time for our swimmers preparing for the upcoming State New Zealand Open championships which double as the trials for the world championships.
"It is important to have a coach who understands the swimmers, the country and what is ahead of them."
Sweetenham has had an involvement with Swimming NZ, producing a review of the high performance structure in 2008. He is contracted until the national championships in mid-March.
Meanwhile, Swimming NZ has advertised worldwide for a new permanent high performance coach. They have already received a significant number of inquiries from several well-qualified and credentialed coaches.