US District Judge Leonie Brinkema has scheduled a hearing on Friday, according to the US District Court in Alexandria in the state of Virginia.
The government has charged Moussaoui, a French national born in Morocco, with being part of an al-Qaida conspiracy that included the 11 September 2001 attacks on the World Trade Centre in New York and the Pentagon outside Washington.
The judge is expected to accept Moussaoui's plea, said Edward Adams, the court spokesman. Brinkema was supposed to have met Moussaoui on Wednesday.
He tried to plead guilty in 2002, but took the plea back a week later.
Moussaoui could face the death penalty, although his sentence would be determined in a trial that would follow any plea.
Lawyers who have followed the case said Brinkema's decision to accept Moussaoui's admission of guilt would hinge on whether she believed he was mentally competent to make the decision, which his court-appointed lawyers deny.
The case has been marked by delays, protracted arguments over access to al-Qaida members in US custody and erratic, belligerent communications from Moussaoui.
Moussaoui is an accused in the
11 September 2001 attacks
The trial has been delayed three times. In March the Supreme Court refused to review an appeals court ruling that denied Moussaoui direct access to three al-Qaida witnesses, who he thinks might support his contention that he was not involved with the 11 September planning.
The court also allowed the government to seek the death penalty, which Brinkema had disallowed.
Eliminating a trial would spare Brinkema the difficult task of working with prosecutors and defence lawyers to draw up unclassified summaries of the three al-Qaida prisoners' statements.
That was the compromise that courts determined was the best way to allow Moussaoui some access to the testimony.
In his handwritten filings, Moussaoui has railed against the US government, Brinkema and his lawyers.
In 2003, Brinkema stripped him of his right to defend himself, saying his legal filings "include contemptuous language that would never be tolerated from an attorney and will no longer be tolerated from this defendant".
In one of his last filings before the judge revoked his right to defend himself, Moussaoui said he wanted "anthrax for Jew sympathiser only," called then-Attorney General John Ashcroft "the Democratic Jerk" and referred to Brinkema as "Leonie you Despotically Judge".