Ballarat Magistrates Court this morning heard Matthew Pring, 31, of Lake Gardens, put lives at risk when he lit the fire on the ground floor section of the store on December 19 last year.

The court heard more than 40 shoppers were in the men's section, about 8.30pm, when Pring was heard by staff saying "there's a fire and it's going to go up".

The court heard Pring, who pleaded guilty to charges including reckless conduct endangering serious injury and burglary, told police during and interview that it had been "hot".

Police prosecutor Senior Constable Gerard Barrow said police asked Pring to comment further and he said: "Merry Christmas".

Magistrate Michelle Hodgson quickly adjourned proceedings in order for a psychiatrist to assess Pring, adding that Pring's offending showed signs of auditory hallucinations.

"It's clear he may be suffering for some kind of psychosis," Ms Hodgson said.

Jon Irwin, for Pring, agreed that his client may be suffering from mental health issues.

Mr Irwin said Pring had been hearing messages in songs and that on the day of the offending at Myer became concerned over a clothing display.

Pring was bailed to re-appear in Ballarat Magistrates Court on May 20 when it is expected that the psych report will be available.