Chancellor Philip Hammond is to say he will manage the public finances in a different way to his predecessor, George Osborne.
Speaking at the Conservative Party conference, Mr Hammond will promise “a new plan for the new circumstances Britain faces” after the Brexit vote.
He will say his “pragmatic” approach allows greater scope for investment to boost the economy.
This will include extra borrowing of £2bn to speed up housing construction.
Leaving the European Union dominated day one of the conference, with Theresa May pledging to trigger Brexit by the end of March.
The economy takes centre stage on Monday with Mr Hammond, who was appointed by Mrs May to replace Mr Osborne when she became prime minister, delivering his speech to delegates in Birmingham.
He will say Mr Osborne’s deficit reduction policies “were the right ones for that time”, adding: “But when times change, we must change with them.”
The government has already confirmed – in the weeks after the Brexit vote – that it has abandoned its target to restore government finances to a surplus by 2020.
Mr Hammond will say the government will still “restore fiscal discipline” but in a “pragmatic way that reflects the new circumstances we face”, promising further details in November’s Autumn Statement.
Alongside Communities Secretary Sajid Javid, Mr Hammond will set out new measures aimed at getting 40,000 new homes built by 2020.
The government will borrow £2bn to support the “Accelerated Construction” scheme, which aims to get houses built on publicly-owned “brownfield” land available for swift development.
Mr Hammond and Mr Javid say the cash will encourage new developers to build up to 15,000 homes in this Parliament.
There will also be a £3bn Home Building Fund to provide loans to stimulate projects, which the government said would build more than 25,000 homes by 2020, with a long-term goal to build more than 200,000.
Mr Hammond’s speech comes after Mrs May addressed the Tory conference on Sunday for the first time as prime minister, with the first day of the gathering focusing on the 23 June vote to leave the EU.
She confirmed she would formally trigger Brexit using Article 50 of the Lisbon Treaty by the end of March 2017, paving the way for the UK to be outside the EU by the summer of 2019.
She also announced a “Great Repeal Bill” would be included in the next Queen’s Speech to remove the European Communities Act 1972 from the statute book and that the UK would become an “independent, sovereign” country.
She said the UK would also leave the jurisdiction of the European Court of Justice and promised to secure “a deal that works for Britain”.