He caused controversy by no-balling Sri Lankan spinner Mutthiah Muralitharan for throwing during last weekend's match between the two sides in Adelaide.

But the Australian Cricket Board insist the decision to replace him has nothing to do with the Muralitharan situation.

Emerson has been absent from his job with the West Australian Office of Fair Trading for the last month, suffering from stress.

"It is the ACB's position that in these circumstances it is both entitled and required to satisfy itself and the cricket public that his admitted medical condition does not impact on his ability to umpire international cricket matches," said ACB chairman Denis Rogers.

"In other words, if he is not fit to be at work, the question has to be asked if he is fit to officiate in a cricket match."

But their view was challenged by Pat Walker, chief executive of the Ministry.

He said: "Mr Emerson's doctor, while indicating that he's not able to work, has indicated that he believes that cricket umpiring is within his present capabilities."

Ranatunga hearing adjourned

Emerson was one of three umpires to call Muralitharan for throwing during Sri Lanka's last tour to Australia in 1995-6.

The spinner's bowling action was subsequently cleared by the International Cricket Council and no other umpire had called him until Emerson did so last weekend.

Arjuna Ranatunga arrives for the hearing in Adelaide

His decision to call him again during the England game prompted Sri Lankan skipper Arjuna Ranatunga to lead his team from the field.

The match resumed after he had spoken with team officials and Sri Lanka eventually won by one wicket.

Ranatunga was later charged with breaching the International Cricket Council Code of Conduct for arguing with the umpire.

But Sri Lanka claim Emerson was unfairly singling Muralitharan out and wanted him removed from Friday's game.

Ranatunga's disciplinary hearing was adjourned on Tuesday after just 90 minutes.

He faces charges including conduct unbecoming an international player, showing dissent, intimidating an umpire and using abusive language.

The ICC could impose a suspension of up to six matches if he is found guilty.