Image caption Alasdair McDonnell said next Tuesday's deadline was artificial and should have been avoided

SDLP leader Alasdair McDonnell has said his party will not be bounced into an artificial deadline on welfare reform.

The party's 14 MLAs have signed a petition of concern on the measure which is to be debated next Tuesday.

Combined with the 28 signatures already collected by Sinn Féin, the SDLP move means the welfare reform bill will be blocked as it will not get the necessary cross community support.

First Minister Peter Robinson said the move would not help welfare recipients.

"Contrary to the comment in the SDLP's u-turn statement this is not an artificial deadline. If they had the least knowledge of the statutory budgetary timetable, they would know that next week is the deadline," Mr Robinson said.

"Nothing in the SDLP's actions changes the legal timeframe. The budget still looms with Sinn Féin and the SDLP indicating that they will do nothing to avoid £600m of cuts to our public services."

He said the debate would go ahead on Tuesday.

Alliance leader David Ford described the move as "reckless" and says the assembly faces its worst crisis in five years.

"We cannot continue to go around in circles on this issue. The future of Northern Ireland's economy and political institutions are at stake," he said.

Ulster Unionist leader Mike Nesbitt said Northern Ireland could not "afford to keep on lurching from one political crisis to another on a regular basis if we want this country and its people to prosper".

Irish Foreign Minister Charlie Flanagan urged all of the parties in the executive "to redouble their efforts in the immediate days ahead to resolve the current impasse over welfare".

'Artificial deadline'

Dr McDonnell said his party has tried to be as constructive as possible over the past three days.

"It's over to others now, we have made our views clear.

"Next Tuesday's deadline was artificial and should have been avoided," he said.

It now looks certain that the assembly will reject the welfare reform package negotiated as part of the Stormont House Agreement, unless DUP Social Development Minister Mervyn Storey withdraws the bill.

The DUP has warned that this would lead to a £600m black hole in the budget and a scenario in which the First Minister Peter Robinson believes the Assembly may collapse.

Sinn Féin has welcomed the SDLP's support for a petition of concern. Conor Murphy called on the DUP to withdraw the bill.

Conor Murphy said the DUP should "re-engage" with other executive parties over welfare.