Treasury funding urged for 25 years
The Treasury should guarantee some financial support over the next 25 years even if Ireland is united, the SDLP said.
Powers over the social security system and to vary taxes such as the corporation levy should be devolved to Northern Ireland in the interim, Margaret Ritchie told business leaders in Belfast.
She said her party wanted to retain the Department for Social Development after the May 5 election but would also be interested in education and health.
And she said long-term there should be more efforts to privatise services and boost enterprise.
"Let us have a 25-year framework, an economic and financial compact with the Treasury which maps out the future in terms of tax-varying powers, the creation of our own social security system and the long-term delivery of the block (grant)," she said.
"One where we undertake to very gradually reduce the subvention in the long-term but with a guaranteed level of Treasury support, even if the constitutional position of the North should change in the meantime. This is the only way we can truly take control of our own future."
According to Ms Ritchie Northern Ireland receives around £8 billion of support from the Treasury to deliver public services. Other estimates are considerably higher.
The Executive's main tool for raising money comes from setting household and business rates.
The Treasury is consulting on allowing the Executive to reduce the level of corporation tax in Northern Ireland to encourage investors but the level of the block grant could fall as a result. The aim is to encourage private enterprise in an economy heavily reliant on public expenditure.
The Northern Ireland Executive is dealing with a £4 billion cut in the block grant.