The American, who has said all year the Sydney Games are among his top priorities, cited "personal reasons" for quitting the team.

Agassi revealed last week that his mother and sister are both fighting breast cancer.

Wimbledon champion Pete Sampras and Jan-Michael Gambill will be offered the chance to take his place.

Agassi is not the first big name to withdraw from the Games. Gustavo Kuerten and Yevgeny Kafelnikov have already said they will not be competing.

Row

Kuerten will miss the Olympics because of a row over shirt sponsorship.

The double French Open champion became embroiled in a dispute involving his sponsors, the Italian firm Diadora, and the Brazilian Olympic Committee (COB).

The sponsors insist Kuerten wears their kit, although he is free to choose his own shoes and racquet.

But Brazilian Olympic chiefs say he must wear its chosen logo, and this has proved a stumbling block.

Kuerten, who crashed out of the US Open in the first round last week, told Brazilian TV he would miss the Sydney Games.

"It's sad to take this decision but I can't break my business engagements," he said .

Wrath

Kafelnikov has incurred the wrath of Russian Olympic officials by pulling out.

He lost in straight sets to Slovakia's Dominik Hrbaty in the third round of the US Open at the weekend, and has not won a singles title all year - for the first time since 1993.

The lean spell has convinced the former world number one there is little point going to Sydney.

"I'm far from my best form at the moment, therefore there is no point at all going to Australia," he said,

Kafelnikov's failure to appear would leave Marat Safin, currently fourth in the ATP Tour Champions' Race, as the only Russian in the men's draw.

It would also prevent Russia from fielding a doubles team.