Chancellor Philip Hammond has guaranteed to continue payments of multiyear EU grants secured by British businesses and organisations up to the point the UK leaves.
The Tory minister said the government was ready to take “whatever steps are necessary” to protect the economy against turbulence.
Thereafter it would support companies as they adjust to life post-Brexit, he added.
Addressing the Conservative conference in Birmingham, he said: “Brexit does mean Brexit and we are going to make a success of it.
“In the meantime I can offer some additional certainty to British businesses and other organisations bidding to receive EU funding while we are still a member.
“I’ve already guaranteed the funding for projects signed prior to this year’s Autumn Statement.
“I can go further. The Treasury will offer a guarantee to bidders whose projects meet UK priorities and value for money criteria.
“If they secure multiyear EU funding before we exit, we will guarantee those payments.”
After Theresa May revealed Article 50 will be triggered by the end of March, this is likely to be in March 2019.
Mr Hammond also announced £220million of new funding for the tech sector to support efforts to transform biomedical and computer innovations into marketable products.
And he hinted at tax cuts to stimulate economic activity, saying “fiscal policy may also have a role to play” alongside interest rate reductions to bolster confidence.
Mr Hammond said action was needed to boost productivity, invest in infrastructure and tackle the “dangerous” gap between London and the “left behind” regions of the UK.