Northern Ireland leaders reach 'workable agreement' on key issues after cross-party talks

David Cameron said he is 'delighted' by agreement

A statue of 1920's Ulster Unionist politician Edward Carson overlooks the grounds of Stormont estate, near Belfast Tuesday (AP)

Northern Ireland's political leaders have reached an agreement on some disputes creating instability at Stormont.

Talks on welfare reform, flags, parades and issues from the past were among those being negotiated in last-ditch talks, which continued overnight and well into the morning.

Crucial to negotiations were the terms of a new £2 billion financial package proposed by David Cameron.

In a message on Twitter, Mr Cameron said: "I am delighted that a workable agreement has been reached that can allow Northern Ireland to enjoy a brighter, more prosperous future."

The participants long passed a deadline of 10.30am set by talks chair Northern Ireland Secretary Theresa Villiers, who insisted the 11 week process would not go beyond the early hours of this morning.

The round table session was focusing on a new heads of agreement document from Ms Villiers setting out areas of potential consensus.

Sleep-deprived politicians had appeared in light hearted moods overnight, with Sinn Fein's North Belfast Assembly member Gerry Kelly tweeting: "Release the Sinn Fein ten from negotiations. It's nearly Christmas."

Additional reporting by PA