A man accused of murdering six people when he allegedly mowed down pedestrians in Melbourne's CBD could be deemed unfit to plead to the criminal charges.
Dimitrious Gargasoulas, 28, faced the Supreme Court of Victoria on Thursday via video link.
He has previously pleaded not guilty to the murder charges along with 28 counts of attempted murder following the alleged car rampage on January 20, 2017.
Prosecutor Andrew Tinney told the court the Crown was seeking reports into Gargasoulas' mental state from a psychologist and a psychiatrist, but these wouldn't be ready until the end of May.
He said reports from Gargasoulas' defence team weren't satisfactory.
However, Justice Lex Lasry raised concerns about how long the matter was taking to proceed through the justice system.
"This is not satisfactory," he told Mr Tinney.
"This matter has got to proceed. In May this year, this matter will be 17 months old."
Reports from Gargasoulas' defence team suggest he had onset schizophrenia from the end of 2016, just before the alleged offending, and that his condition was treatment-resistant.
One of the defence reports also suggested Gargasoulas was suffering drug-induced psychosis.
Justice Lasry adjourned the matter for a directions hearing on May 21, when he may rule on whether there is an issue of Gargasoulas' fitness to plead.
If he determines there is an issue, the matter will head to a special hearing on June 12.
A special hearing determines whether an accused person committed a crime or is not guilty because of mental impairment.