Two sections of the Rattray St building, with a rateable value of $355,000, collapsed on Wednesday, and a section of the street outside the building at No 175 will remain closed to traffic for up to a week.
By then it is hoped the the former commercial warehouse will be considered safe.
The future of the Dragon Cafe, which has been located in the ground floor of the building for the past 50 years, also remains under a cloud as engineers continually reassess the stability of the building.
Matthew Williams, of CPG, the engineering consultancy in charge of the building repair work, said its priority was to safeguard the public by stabilising the building.
"We are trying to save as much of the heritage aspect of this building as possible and are liaising with all affected parties, including the Historic Places Trust, over all parts of the building we will remove."
Dragon Cafe owner Jack Ng, of Dunedin, said its interior remained unscathed, and he was confident the business would reopen once the building was repaired and safe.
He inspected the cafe after the collapses on Wednesday, and had removed all frozen food from the powerless premises.
"Down in the restaurant there's nothing damaged. It's only up the top."
Mr Ng - who has owned the cafe for the past 11 years - said he was not sure how long the business would remain closed, as work to stabilise the building "might take about a week".
"We were due for a couple of weeks break anyway," he said.
Mr Williams said contractors would focus on removing most of the building to the level of the top storey windowsills.
The roof structure would be removed where possible, and secured, the facade would be propped up, and the building made watertight.
The work would take up to a week and once safe, people would only be allowed on site on essential business.
The road around the building area would remain closed until the building was safe.
The Crown Hotel bar was open and a footpath allowing access to businesses on the north side of the street was open.
The building would then be assessed further and all interested parties would be consulted on a long-term plan for its future.
As they removed the unsafe parts they assessed the remaining structure for its safety, and the plan was subject to change because of the deteriorated condition of the building, Mr Williams said.
