Around 300 state-owned buildings are currently unused, and while the priority is to sell off unused assets, in the meantime they will be let out as part of the campaign to help small firms.
The Prime Minister believes the extra office space will help companies grow, boosting the economy.
The Federation of Small Businesses gave a cautious welcome to the plans.
“Rent is one of the highest overheads a small enterprise faces, and it is important that there is affordable property out there,” said Andrew Cave from the industry body.
However, as the government is planning to sell much of the space, it describes the planned leases as “flexible, short-term arrangements.”
“Small firms crave certainty,” said Cave.
“The government will need to provide some degree of certainty on how long companies can use the offices, and some may be put off renting the space if that cannot be given.”
The plans are not yet ready to be put in place, with areas that will benefit the most still to be identified.