Michael Jackson's doctor has pleaded not guilty to involuntary manslaughter over the death of the pop star.

Dr Conrad Murray - accused of giving the King of Pop a fatal dose of an anaesthetic to help him sleep - appeared in court in a grey suit and burgundy tie as the singer's father Joe, mother Katherine, and siblings LaToya, Jermaine, Tito, Jackie and Randy watched from courtroom seats.

Neither Murray, 56, nor the Jacksons showed much emotion as the 6ft 5ins doctor entered his plea through his attorney Ed Chernoff, but as he emerged from court, family patriarch Joe Jackson declared: "We need justice."

Murray was released on 75,000 dollars bail.

Superior Court Judge Keith Schwartz ordered him to turn in his passport and said he could travel within the US, but not to any foreign country. The prosecutor had suggested he might flee to his native Grenada or to Trinidad, where he has a child.

Murray was ordered to return on April 5 to have another date set for his preliminary hearing. That proceeding will disclose the evidence prosecutors maintain will demonstrate his "gross negligence".

Schwartz told Murray he was restricting his practice of medicine, barring him from using any anaesthetic agent, specifically the drug propofol.

Outside the Los Angeles airport area courthouse, about 50 Michael Jackson fans carried large photographs of the superstar and signs urging 'Justice For Michael'.

Murray, a Houston cardiologist who was with Jackson when he died on June 25, entered his plea just hours after he was charged.