Peter Robinson and Martin McGuinness are in London for talks with British Prime Minister Gordon Brown.
The Northern Ireland First and Deputy First Ministers are seeking guarantees of additional funding from the British Exchequer.
The meeting comes in advance of tomorrow's first meeting of Northern Ireland's power-sharing executive since June.
Both leaders are thought to be keen to publicise today's meeting, but Mr Robinson and Mr McGuinness have held a number of meetings with Mr Brown and NI Secretary Shaun Woodward in recent weeks.
The two leaders are said to be pressing for British Exchequer funding on a number of fronts.
There is the problem of an equal pay award for civil servants, backdated to pre-Assembly days.
They also want funds that would allow the Executive to delay the introduction of water rates for at least another year.
The two NI leaders are worried that when justice and policing powers transfer from Westminster to Stormont, there will be huge bills for renovation of court houses and police injury compensation claims.
Mr Brown and Mr Woodward are thought to attach huge significance to tomorrow's resumption at Stormont.
Because of this, announcements about British Exchequer funding on a number of fronts are expected to be made in the coming days.
