The Government's public spending plans for Northern Ireland will hit policing and justice powers and stymie investment, the Executive has warned.
Peter Robinson and Martin McGuinness are to seek a meeting with Prime Minister David Cameron after a special gathering of ministers which lambasted the Northern Ireland Secretary for becoming the "Treasury's spokesman".
They want the coalition to honour the previous Government's pledge of an extra £18 billion for infrastructure investment between 2005 and 2017.
Deputy First Minister Martin McGuinness said: "They, I think, are going to plunge us deeper into increasing levels of unemployment, not just in the public sector but in the private sector."
Political leaders have claimed cuts unveiled by Chancellor George Osborne on Wednesday amounted to a £4 billion loss for the Stormont purse over the next four years, sparking predictions of 50,000 job losses.
The Executive statement said: "Ministers are concerned about the potential consequences for the investment strategy. Worries were also expressed about some of the financial arrangements for the devolution of policing and justice."