THE trial date for a US Army private accused of passing a trove of secret documents to WikiLeaks has been pushed back from February to March next year, a military judge said Sunday.

The court-martial of Bradley Manning, 24, charged with the most serious security breach in American history, previously had been scheduled to begin on February 4.

But the judge, Colonel Denise Lind, announced at a pre-trial hearing north of Washington in Fort Meade, Maryland that more time was needed to handle various motions from both the defence and prosecution.

Due to last about six weeks, the court-martial could begin March 6 or 18, depending on the pace of legal proceedings, the judge said.

The latest round of pre-trial hearings that began Tuesday has focused on Manning's detention for nine months at a brig in Quantico, Virginia.

The defence argues the case should be dismissed because of what it calls unduly harsh treatment Manning received at the US Marine Corps jail, where he was held under strict "suicide watch" measures against the advice of two military psychiatrists.

The government maintains he did not suffer illegal punishment and that commanders wanted to ensure Manning did not take his life.

Legal experts say it is unlikely the charges will be dismissed based on the allegations over Manning's detention, but the judge could take the issue into account during sentencing, if the army private is found guilty as charged.

If convicted on all 22 counts, including a charge of "aiding the enemy," Manning could spend the rest of his life in prison.

Originally published as WikiLeaks suspect's trial date postponed