Economy secretary Derek Mackay confirmed the cash amid frustration from business owners and residents shut out of a safety cordon around the site while the building is dismantled.
The Scottish Government said Glasgow City Council would be given the extra funding to distribute to businesses inside the cordon and those in the wider Sauchiehall Street area who could demonstrate hardship as a result of the fires.
Those firms within the Glasgow School of Art and Victoria’s cordons will receive £20,000 of direct financial support. Other businesses in the area impacted are eligible for £10,000.
The move follows rates relief for affected businesses and grants of £3,000 for affected residents.
Mr Mackay said: “The terrible fires at the Glasgow School of Art and Victoria’s are having a significant impact on many local businesses who are either closed or unable to access their premises.
“Given the scale of the on-going disruption, I am making up to £5 million available immediately to support those businesses affected.
“The sheer scale and lasting effects of the fires on those involved are becoming clear and it is important that businesses are given financial support to help them through this very challenging time.
“This funding will also help minimise the impact on the economy of the city as everyone involved works to help businesses and residents return to their premises as quickly and safely as possible.”
Glasgow City Council leader Susan Aitken said: “The Victoria’s and School of Art fires have had a significant adverse impact on businesses at both ends of the street.
“The council has been working closely with the Scottish Government to facilitate this fund, which we hope will assist those business affected by both events.
“This fund complements the range of actions that we have taken in the past few weeks to support businesses including the use of the Glasgow Guarantee to support employees, having dedicated business support advisers based in the Dental Hospital and the Savoy Centre, supporting businesses to relocate outwith the cordon, hosting a session on insurance and legal issues with Harper McLeod, introducing zero rating for businesses in the cordons and reduced rates for businesses who can demonstrate detrimental impact.
“Additionally, I have convened a Sauchiehall Street taskforce that is working on plans for the future viability and vibrancy of the street.”
Applications for the new fund will open on 31 July with eligibility for businesses outside the cordon still to be set out.