Businesses and 33 homes within the cordon zone remain evacuated following the blaze which tore through the Mackintosh Building on the night of June 15.
Glasgow City Council said that parts of the building are at risk of “sudden, unannounced, collapse” and it is being dismantled on safety grounds.
Locals have been left frustrated that they cannot access their property and said they may try to breach the cordon to retrieve possessions.
A Notice of Entry form circulated by the Garnethill Displaced Residents Group and Sauchiehall Street Inner Cordon Business demands access to their properties starting on Sunday.
It states: “This will be accomplished in an orderly and peaceful manner in succession, one at a time, and for a period of 10-20 minutes, having full understanding and recognition of the risks associated therewith.”
The fire took hold amid a major restoration project following another large blaze at the Charles Rennie Mackintosh-designed art school in 2014.
Nearby properties including music venue the O2 ABC were also affected by the latest fire.
Annemarie O’Donnell, chief executive of Glasgow City Council, said that the site is dangerous and warned people not to breach the cordon.
In an email to the two groups on Friday she wrote: “This email is to make it clear to you that you should not breach the cordon at any time until Glasgow City Council’s building control officers have declared that the GSoA and ABC buildings are no longer dangerous. This is because the building may be subject to a sudden, unannounced, collapse.
“The building has suffered significant trauma, as a result the walls have moved in ways which will certainly lead to parts of the building collapsing.
“That collapse could happen without warning. Anyone in any adjacent buildings in the path of falling masonry would be at risk of death.
“I note from your letter that you intend to take this action ‘having full understanding and recognition of the risks associated’. However the law compels the council to protect life, regardless of whether you wish to accept that risk.”
She added: “I should tell you that I have today spoken to Police Scotland who will increase their presence at the cordon and may arrest anyone attempting to breach it.”
The local authority is making a hardship fund available in co-operation with the Scottish Government, with each affected household able to apply for £3,000.
The council said it has also been writing to insurers to confirm that residents and businesses cannot access their property as it is within a public safety cordon.
Police said that officers remain at the cordon for public safety purposes.
A police spokesman said: “The building has been deemed dangerous by Glasgow City Council and anyone who enters the cordon is putting themselves at risk.
“If anyone enters the cordon they may find themselves arrested, however, this would be on the grounds of concern for their safety and in order to protect them.”