The Executive could be left with a multimillion-pound bill for a new cross-border bridge, Sammy Wilson has warned.
In October the European Union said it would give 17.4 million euro (£14.1 million) to fund the single-lane cable bridge. It will run between Co Louth and Co Down, will be 660 metres long and could be open by 2015.
Finance Minister Mr Wilson said: "If this bridge is not completed on time, the final bill being in by June 2015, then we lose all of the money which has been put into this project."
He told the Stormont assembly £2.8 million would be paid by the Executive for the bridge, with most of the money coming from the Department for Regional Development.
The business case is still being considered by his finance department.
Mr Wilson added: "It would be most inappropriate for me as minister to make a judgment either way, that I am supporting this project or that I am opposing this."
Planning permission has been granted by authorities on both sides of the border.
SDLP South Down MLA Sean Rogers said the bridge would boost jobs and the economy. "What a difference an investment of £20 million can make to South Down. This is a win-win for construction, the hospitality and the retail sectors in South Down and further afield," he said.
The SDLP motion before the assembly has called on the executive to express its support for the project.