Whitehall departments are being instructed to draw up plans to sell off billions of pounds worth of land and other public sector assets.
Chancellor George Osborne will confirm the public sector spending review - due on November 25 - will require departments to find a further £20 billion in savings over the next four years.
For the first time they will be specifically asked to identify how they will contribute to the Government's target to dispose of sufficient public sector land to build 150,000 new homes by 2020.
A document, setting out the scope of the spending review, will confirm plans for extra investment in the NHS and defence.
However it will also point out that the Ministry of Defence alone currently owns around 1% of all the land in the UK – some 227,300 hectares.
Altogether, despite £1.7 billion worth of disposals in the last parliament, the Government still owns more than £300 billion worth of land and buildings it will say.
Mr Osborne will say that the further savings - which follow the £12 billion in welfare cuts and £5 billion from tackling tax avoidance announced in the Budget - will complete the Conservatives' plan to eliminate the deficit in the public finances.
He will argue the strength of Britain's economic recovery means that the time is right to press on with plans to run the biggest structural budget surplus for 40 years.
Treasury Chief Secretary Greg Hands is now writing to ministers instructing them to start drawing up plans to deliver the necessary savings over the next four years.
Mr Osborne and Mr Hands will say: "Over the last parliament the Government delivered the reductions in public spending that it committed to and more than halved the budget deficit it inherited.
"We honoured our promise to increase spending in vital public services such as the NHS and schools, and our reforms improved the quality of public service delivery.
"But we are still borrowing £1 for every £10 we spend and national debt remains at its highest level for 50 years. If we do not deal with this debt, we run risks with our economic security."