The sentencing of David McBride is set to begin in May after lawyers for the military whistleblower asked to delay proceedings to respond to new evidence.
In the ACT Supreme Court registrar's list on Thursday, McBride's sentencing hearing was scheduled to take place over two days on May 6 and 7.
The former military lawyer, who leaked classified defence documents to journalists, was initially set to face the start of sentencing next week.
McBride previously pleaded guilty to three charges relating to the theft and disclosure to journalists of classified documents, which detailed alleged misconduct by Australian troops in Afghanistan.
On Wednesday, lawyer for McBride, Emmanuel Kerkyasharian, asked for sentencing to be delayed, saying the defence needed time to respond to new evidence.
Mr Kerkyasharian said the prosecution planned to file an affidavit from a high-ranking official in the Australian Defence Force, containing "a series of contentions on what would arise on the speculative dissemination of documents to the public".
He told the court the parties were still in negotiations to agree to a statement of facts outlining the crimes.
The court may need to be closed to the public at times during McBride's sentencing in order to discuss evidence sensitive to national security.
Justice David Mossop has said "we may have to go full spooky in terms of court set up".
McBride was set to face a jury trial last year, but a decision ruling classified documents were protected via public interest immunity, coupled with a pretrial ruling on jury directions, resulted in a "fatal blow" to the defence case.