Bosnich has been admitted to a depression unit of a medical facility just days after he was widely reported as failing a routine drugs test.

A statement released by the 30-year-old's management company, SEM, read: "Mark Bosnich has been diagnosed as suffering from severe clinical depression."

The statement continued: "On medical advice he was admitted to a depression unit of a medical facility to obtain treatment for that depression.

Bosnich's location is being kept secret, but he has referred allegations that he tested positive for cocaine to his lawyers.

Neither UK Sport, which carried out the test, the Football Association nor Chelsea have confirmed the identity of the player.

Bosnich was reportedly tested and the results leaked.

Under drug testing rules, if a player initially tests positive for a banned substance, a test must then be carried out on a second urine sample, the B Sample.

UK Sport has yet to set a date for the test on the B Sample.

Should it prove positive, the FA will have to decide on disciplinary action.

Bosnich could face up to a year's worldwide ban from the game, while Chelsea will examine if they have grounds to rip up Bosnich's �40,000 a week contract.

Chelsea issued a statement which said: "We cannot comment on the allegations of drug violations made against one of our players.

"Any testing undertaken is in accordance with the doping regulations laid down by the football authorities and remains a private matter between the club, the player and the football authorities."

An FA spokesman said: "We cannot confirm or deny whether or not a test has been carried out.

"We do not discuss anything to do with the FA's drug-testing programme."

Bosnich was expected to be the natural replacement for Peter Schmeichel when he moved to Manchester United from Aston Villa in 1999.

But he only made a handful of appearances and his fitness was criticised by Sir Alex Ferguson.

Following his free transfer move to Chelsea in January 2001, he fell out with manager Claudio Ranieri after refusing to travel to Wales for a pre-season match.