Jury still out on Bourke St driver fitness

A Melbourne jury will enter a third day of deliberation about whether murder-accused Bourke Street driver James "Dimitrious" Gargasoulas is fit to stand trial.

The 12 jurors will on Thursday continue their discussions behind closed doors to try and reach a unanimous decision on whether the 28-year-old is mentally fit to face trial.

Gargasoulas is accused of running down pedestrians in the city in January 2017, killing six people, including two children.

He's charged with six counts of murder and 28 of attempted murder.

Experts, including three psychiatrists, gave evidence during the Supreme Court investigative hearing, with two of the specialists believing Gargasoulas is not fit to stand trial.

Justice Lex Lasry can discharge the jury without a verdict if they can't agree.