In a statement, the government said it had been talking the trade to find ways to reduce the pressure on ambulances and to speed up the admission of people who had tested positive.
From Monday, the Fire Services Department will divert cases to the bus fleet and drivers will take patients from their homes to isolation facilities.
The fleet size will be adjusted according to the actual demand, officials said.
Drivers of these coaches must wear protective gear and be tested before they start work every day, while the buses will be disinfected.
The coaches will be marked with special labels and will not provide other services.
Currently, officials have also enlisted the help of taxis to transport Covid patients with mild symptoms to and from designated public clinics.