Former U.S. Open champion Michael Campbell says he has lost the motivation to play top-level golf and is quitting to concentrate on teaching.

The 46-year-old New Zealander, who won the Open at Pinehurst in 2005, told New Zealand's Radio Sport on Saturday retiring was a hard decision but "I have no complaints to walk away from the game that has given me such a wonderful life."

Campbell lives in Malaga, Spain where he runs a golf academy and has plans to establish others in Asia and New Zealand. He told Radio Sport he hopes to play on the seniors tour when he becomes eligible in four years.

He said friends of the same age "are still out there competing ... but right now I have got no motivation to play."