Finance Minister Sammy Wilson said the estimated cost of delaying reform of public service pension schemes was £260m a year, on 26 November 2012.
Mr Wilson told the Assembly he was "very disappointed" that the Executive had failed to agree to his recommendation for a legislative consent motion on the reforms.
This would have passed control of the reforms to Westminster for legislating on a UK-wide basis.
Mr Wilson said this financial bill could be equal to 8,000 full-time nurses.
He said the best way forward now was speedy legislation at Stormont to minimise as far as possible the financial penalty and meet the deadline of April 2015.
Daithi McKay of Sinn Fein who chairs the Finance Committee said they would not not be found wanting in progressing the bill through the legislative process.
Alban Maginness of the SDLP said public sector workers were right to be concerned for their pensions.
Mr Wilson said the SDLP appeared to be "schizophrenic" on the issue.
The second part of the debate can be viewed