UPDATE 20/11 - Grocon has been handed less than the maximum fine after the deadly event, in a ruling heavily criticised by the CFMEU.

ORIGINAL 18/11 - The maximum fine that building firm Grocon can receive for a wall collapse that killed three people has been called “a slap on the wrist”.

Grocon faces a maximum fine of $305,000 for pleading guilty to a criminal charge of failing to keep a safe workplace, following the tragic incident in 2013.

The potential fine comes after Magistrate Charlie Rozencwajg said he would hear the case against Grocon (Victoria Street) Pty Ltd – an arm of the larger Grocon group – in Melbourne Magistrates Court instead of referring it to the higher County Court.

Three people died when a section of a wall on Grocon's CUB building site in Carlton fell on them in high winds early last year.

WorkCover OHS inspectors saw a “bow” and lack of symmetry in the double brick wall that was left standing, after the wall and 80-metre advertising hoarding attached to it fell.

The court has heard Grocon will plead guilty to one charge, leading prosecutors from the Victorian WorkCover Authority to drop the remaining five charges against the Grocon group.

The deal hinged on Mr Rozencwajg opting to hear the case.

The decision to do so means the company faces a maximum fine of $305,000 - much lower than the $1.1 million maximum fine applicable in the County Court.

Construction, Forestry, Mining and Energy Union national secretary Dave Noonan has slammed the potentially low penalty.

“Unfortunately Grocon are likely to receive a mere slap on the wrist, a fine. That means nothing to a multi-million-dollar corporation,” he told News Corp reporters

“The union, for its part in campaigning and demonstrating for safety on Grocon sites, has been fined over $1 million, so I think that Victorians today need to reflect on what is the value of safety in the workplace, what is the value of a life?

“We think that workers who get killed on Victorian construction sites, and members of the community in this case who have died as a result, frequently don't get justice. We believe [the authority] needs to do a much better job and be properly resourced in doing that job.”

Prosecutor Greg Lyon, QC, says WorkCover Victoria could not prove beyond reasonable doubt that Grocon and Aussie Signs - the company contracted to attach the large sign - caused the wall to fall.

A plea hearing for is scheduled for this week, while a committal hearing for Aussie Signs will continue on Friday.