Serb ultra-nationalist leader Vojislav Seselj, who is on trial in The Hague for war crimes, is being treated in a Dutch hospital for an undisclosed ailment, the court said Wednesday.

"I can confirm that he (Seselj) is still receiving treatment," said International Criminal Tribunal for the former Yugoslavia (ICTY) spokeswoman Nerma Jelacic.

"He is receiving the best possible care that can be afforded in the Dutch health system," she told reporters, describing his condition as stable.

Seselj, 57, went on trial in November 2006 for his alleged role in the persecution of Croats, Muslims and other non-Serbs and their expulsion from areas of Croatia, Bosnia and Serbia between 1991 and 1993.

He faces nine counts of war crimes and crimes against humanity including persecution, murder, torture and cruel treatment.

A Serbian media report this week quoted one of Seselj's legal advisors, Zoran Krazic, as saying his client's illness was caused by a "heart or lung failure" with him "practically experiencing clinical death".

Jelacic said however: "I am able to refute the claims of clinical death of the accused," adding that Seselj's wife had visited him in hospital.

"I reiterate that Seselj's health is stable, his life is not in danger and his condition is not life-threatening according to the information we are receiving on a daily basis from the medical personnel treating him."

Seselj, who has been held at the ICTY's UN detention unit in The Hague since surrendering in September 2003, has also been convicted on two counts of contempt of court, for which he has to serve 18 months in jail.