Teenage siblings Alexander and Bridget Jones and Frenchwoman Marie-Faith Fiawoo, 33, died on March 27, 2013, when a 20-metre section of the wall and wooden hoarding fell in high winds.

Construction giant Grocon was later fined $250,000 after pleading guilty to failing to ensure a safe workplace at the vacant Carlton and United Breweries site in Swanston Street.

In Melbourne Magistrates Court on Monday, Jonathon Westmoreland, 30, from Wandin North, pleaded not guilty to a charge of doing building work without a permit over several days in October, 2011.

Prosecutor Paul Holdenson QC told the court that Mr Westmoreland's business traded as Paramount Signs and was not a corporate entity.

Mr Holdenson, with Andrew Woods for the Victorian Building Authority, said in his opening to a planned six-day hearing that the accused and three workers constructed the plywood hoarding attached to the brick wall.

Defence barrister Peter Haag told magistrate Carolene Gwynn that his client was not legally empowered to apply for a building permit.

Before the case began, Ms Gwynn noted that the hearing was booked in for six days and asked If it was correct that all attempts at resolving the matter had been "exhausted".

Mr Holdenson said that they had.

The first prosecution witnesses called had worked with Mr Westmoreland on constructing and attaching the plywood hoarding to the brick wall.

Paul Livesay, a mechanic, agreed with Mr Holdenson that the accused was the "boss" and also had worked on the job.

Mr Livesay said he had signed a "job safety analysis" before work began with a Grocon employee but he did not know if a building permit had been issued for work on the site.

Signwriter Daniel McMahon said he had done a "bit of everything" on the job and had attended a "tool box meeting" with the Grocon representative but he also could not recall a building permit being issued.

Ashley Taylor, a stone mason who is still employed by Paramount Signs, said he was told by Mr Westmoreland "what to do" and had not seen a building permit or heard anyone discuss one.

Guissepe Genco, the City of Melbourne's building surveyor, told the court the masonry brick wall ran for about 70 metres and the hoarding for about 20 metres of that length.

Mr Genco said about 20 metres of the wall collapsed and between 1.8 and two metres of the plywood hoarding had fallen.

He told Mr Holdenson that checks of council records had not found a building permit having been applied for or issued for the site in October, 2011.

In an unsworn statement by Mr Westmoreland in April, 2013, that was read in court by Mr Holdenson, he admitted he did not obtain any planning or building permits for the work because he did not deem it his responsibility.

He said he had been "totally distraught" since learning of the deaths and that he had "questioned myself every day since". He said in the statement that if there had been "any issue with the integrity of the wall I would have voiced my concerns".

Cameron Davey, a compliance officer with the Victorian Building Authority, said in evidence that Mr Westmoreland told him in an interview in December, 2013 that he had no formal building qualifications but had been a carpentry apprentice for two years.

In the interview, Mr Westmoreland said the company Aussie Signs subcontracted the work to his brother's company who then engaged Mr Westmoreland.

The hearing continues.