Northern Ireland First Minister Arlene Foster said she would "not put a figure" on how much money she will demand when she meets Boris Johnson in Belfast.
Speaking to BBC Radio 4's Today programme, Ms Foster said the six counties of Northern Ireland required funding to properly resource public services and invest in infrastructure after parties agreed a deal to re-open the Stormont Assembly last week.
She said: "It's a composite figure. There's a need to make sure that we have the resources, resources not just for one year but over a number of years so that we don't face a cliff edge in another year.
"But as well as that, we need to have capital investment. We have a huge hole in our infrastructure, particularly in our water infrastructure which we need to fix.
"It's a package that will have to be capital and resource, and I think the Prime Minister is very much aware of what we need."
Asked whether the figure being asked for was up to £2 billion, the DUP leader said she was "not going to put a figure on it because I think it is important that we get the right figure".
Ms Foster said Brexit and the Withdrawal Agreement would also be on the cards when she meets with Mr Johnson.
She told the BBC: "I was very concerned about that deal in October, and I make no apologies for that.
"But since then the Prime Minister has been saying very clearly that he will ensure that there is unfettered access.
"I want to hear from him today how he's going to do that and how the regulations that are coming forward are going to make sure that there aren't any barriers between Northern Ireland and the rest of the United Kingdom, because the rest of the United Kingdom, Great Britain, is our biggest market, both in terms of what we send to them but also what they send to us."
Mr Johnson and Taoiseach Leo Varadkar will travel to Belfast on Monday to meet the leaders of Stormont's freshly restored executive.
Their visit comes less than 48 hours after a special sitting of the assembly saw devolution return for the first time in three years.
The first meeting of the restored Northern Ireland Executive is scheduled to take place tomorrow.
Ahead of the leaders' visit, Stormont's newly-appointed finance minister warned that cash pledged by two governments to secure last week's deal must now be delivered.
Sinn Féin's Conor Murphy said the parties had done their part by restoring power-sharing and it was time for the governments to honour their pledges on funding.
The bulk of the new funding linked to New Decade, New Approach will come from the Treasury, with an expectation that it could add up to billions of pounds.
Read More: Climate change and flag-flying pledges included in Stormont deal
The cash is expected to front load efforts to resolve the deepening health crisis, with tackling the healthcare workers' pay dispute and spiralling hospital waiting lists topping the list of priorities.
The Irish government will honour commitments to part-fund some north/south projects, such as the A5 dual carriageway and a redevelopment of the Ulster canal system.
Read More: Analyis: The Executive is back - but hard work has only begun
Mr Murphy said the deal secured last week by the two governments contained "ambitious commitments for public services and workers".
"To deliver these commitments, the governments pledged a substantial injection of funding, over and above the block grant," he said.
Read More: Ambitious plans to 'transform' health service welcome but challenging to deliver
Mr Johnson said Stormont could now "move forward with improving people’s lives".
"I look forward to meeting with the new executive and hearing about their plans for the future - including driving forward much needed reforms to public services and resolving the current health strike," he said.
Who's who in the Stormont executive?
- First Minister: Wounded Arlene Foster cannot afford another misstep
- Deputy First Minister: Michelle O'Neill facing huge test to follow Martin McGuinness
- Agriculture, Environment and Rural Affairs: Edwin Poots a veteran of previous executives
- Finance: Conor Murphy an experienced voice on executive for Sinn Féin
- Health: Robin Swann a surprise choice for challenging portfolio
- Economy: Diane Dodds returns to Stormont after 13-year absence
- Infrastructure: Nichola Mallon to benefit from government cash pledges
- Communities: New deal provides breathing space for untried minister Deirdre Hargey
- Eduction: Peter Weir will find education system in more perilous position than when he left
- Justice: PSNI recruitment will need careful handling by Naomi Long
