The man accused of driving a car that slammed into pedestrians in the heart of Melbourne's CBD has been charged with 18 counts of attempted murder.

Saeed Noori, 32, appeared in the Melbourne Magistrates' Court on Saturday afternoon and did not apply for bail.

The Heidelberg West man put his head in his hands and became emotional when he saw his mother during the short out-of-sessions hearing.

He is also facing one count of conduct endangering life.

Saeed Noori has been in police custody since Thursday afternoon. ( ABC News )

Mr Noori was arrested on Thursday minutes after a four-wheel drive sped down busy Flinders Street at 4:40pm, crashing into pedestrians.

Police were initially unable to question him, but he was taken to police headquarters in West Melbourne to be interviewed this morning.

The 19 charges were laid hours later.

The court was told the motivation for attack remained under investigation and further charges were being considered.

Mr Noori's lawyer told the court his client's mental and physical health would be an issue while he was in custody.

The magistrate ordered a psychiatric assessment.

Saeed Noori was initially apprehended by an off-duty police officer. ( News Video )

Nineteen people were taken to hospital, where 12 remain. The court heard three are in a critical condition.

Nine of the injured people were foreign nationals from countries including South Korea, China, Italy, India, Venezuela, Ireland and New Zealand.

Mr Noori's mother cried when her son entered the courtroom. She did not comment to the media outside when she left.

He will appear in court again on Wednesday.