Michael Jackson at the courthouse in Santa Maria, California. (AFP)

Santa Maria (California), March 10 (Reuters): Michael Jackson, looking pale and shaky, arrived today at his sex- abuse trial from a hospital a few minutes after the deadline set by the judge who had given him one hour to get to court or risk jail and forfeiture of his $3 million bail.

Santa Barbara county superior court judge Rodney Melville, had issued an arrest warrant against Jackson after he failed to show up at the start of proceedings on what was expected to be the most crucial day of the trial ? testimony by his young accuser.

It was not immediately clear what action the judge would take against Jackson, who was forced to race from a hospital emergency room to the courthouse. The singer walked slowly, taking the arm of an aide, and was dressed in what appeared to be pajama bottoms under a dark jacket.

Jackson?s 15-year-old accuser was to have begun his second day on the witness stand today.

Jackson?s attorney explained that the 46-year-old entertainer had gone to hospital with an unspecified back problem. A hospital spokeswoman confirmed Jackson spent 45 minutes in the emergency room at Santa Ynez Valley Cottage Hospital. She gave no details.

Jackson is accused of sexually molesting a teen cancer survivor and plying him with alcohol at the entertainer?s Neverland Valley Ranch in 2003. The pop star, who has pleaded innocent, is also charged with conspiring to commit child abduction, false imprisonment and extortion. He could face more than 20 years in prison if convicted on all 10 criminal counts.

Melville, who began the court session promptly at 8.30 am, noticed immediately that Jackson was not seated at the defence table. ?I?m issuing a warrant for his arrest and forfeiting his bail,? Melville said, speaking over a bid by Mesereau to speak on Jackson?s behalf. ?I?ll hold the warrant for one hour to give him time to be in court. After that, I?ll issue the warrant.?

The judge then announced that the court was in recess and walked off the bench.

Yesterday, the boy who accuses Jackson of sex abuse glared at the pop star as he took the witness stand.

?Yes, that?s Michael Jackson,? the 15-year-old boy answered firmly when asked by Santa Barbara county district attorney Tom Sneddon to identify the famous defendant sitting about 3.5 metres away from him in the courtroom.

Wearing a crisp blue shirt and dark pants, the boy stared defiantly at Jackson, 46, as he was ushered into the courtroom and onto the witness stand. He spoke firmly and clearly, in contrast to his brother and sister who during their testimony often mumbled and did not appear to look at Jackson.

The boy, who met Jackson at his Neverland Valley Ranch in 2000 while suffering from a cancer that doctors had predicted would kill him, is the prosecution?s star witness.

The boy told jurors that Jackson invited him to Neverland for the filming of a documentary about the pop icon, then pulled him aside and asked him to embellish their relationship on camera.