Sinn Fein last night toned down its threat to pull out of the Northern Ireland Assembly over the delay in delivering key pledges on policing and justice.

The party's MEP Mary Lou McDonald said she was hopeful that when First Minister Peter Robinson returns from holidays there would be more "substantial engagement" on devolving powers.

Her comments followed a stern warning from the party's Dail leader Caoimhghin O Caolain that Sinn Fein would pull out of the Assembly if there was no movement on long-standing pledges.

"If we are forced to conclude that change will not be forthcoming from the Executive then we will have no option but to pull out our ministers and seek to put pressure . . . on the British government," he said.

That threat prompted an angry reaction from the DUP's Jeffrey Donaldson, who described the remarks as "unhelpful" and called for Sinn Fein leadership to clarify the comments yesterday.

During a press event on the Lisbon Treaty fallout in Dublin, Ms McDonald appeared to tone down the original threat made by Mr O Caolain.

"It's very clear we need to deliver any agreements that we've had with the DUP and the two governments. The devolution of policing and justice has to happen. We, in our party, have worked for years and are very committed to the process under way, but we need to start seeing results," she said.

"We have agreements in terms of justice and policing, in terms of the Irish language act, and so on, and we want to see those delivered on.

"It's not a case of threatening anything. It's just a case of recommitting ourselves to actually delivering."

Over the summer, she said the party tried to negotiate with the DUP with little success.

"It hasn't amounted to very much quite frankly. We are hopeful that when Peter Robinson returns from his holidays, we will have a more substantial engagement," she said.

"But be very clear about this, we need the devolution of policing and justice powers as agreed; we need the Irish language Act; we need all the outstanding issues resolved. We are committed to delivering that. We need the DUP and everyone else on board."

Her party colleague Aengus O Snodaigh said it was time to resolve outstanding issues to provide for "stable institutions".

Earlier this month Sinn Fein and the DUP reached agreement in principle that there should be one Justice Minister in Stormont Executive.

On Sunday, at a republican gathering in Co Cavan, Mr O Caolain said republicans were growing increasingly concerned at the lack of progress on devolution. The DUP has since insisted it remains committed to resolving the deadlock.