The party pledged it will seek the plebiscite which should be timed when an Assembly and Executive are "operating stably".

And the SDLP blueprint said it would campaign "vigorously" in favour of a 'yes' vote.

Apart from an all-Ireland Corporation Tax of 12.5%, the party said it would also establish an all-island economic policy unit including a growth loan and equity fund to increase business start-ups, and a cross-border economic development zone.

SDLP leader Mark Durkan said the election represented a choice between stop-go politics, delay and delivery, and "sharing only contempt for one another or delivering the prospect of a truly shared society."

But sounding a warning against the promises politicians make during election periods, Mr Durkan also denied the 48-page document demonstrated a lack of socialism or would fuel the fears which could lead SDLP voters to stay at home.

Mr Durkan said Direct Rule has done real damage since the last Assembly Election in November 2003 and was "lining up" still more.

"The same result as the last time will only produce more of the same: more suspension; more stalling; more direct rule and an ever tighter squeeze on hard working families and on our public services," he said.

Northern Irish politics cannot afford any more stalling, stunts or stand-offs, the SDLP leader warned yesterday as the party launched its election manifesto.

He said: "When good people don't vote, bad politicians get elected" .

Only by coming out to vote could people hope to end the undoubted uncertainty over the restoration of devolution - and left to themselves the DUP and Sinn Fein could not make it work.

The SDLP manifesto also calls for:

• Two new Assembly committees to examine the cost of administration and policy delivery

• A Commissioner for older people

• Replacing A-levels and ensuring the end of academic selection.