Talks aimed at ensuring the stability of the Northern Executive and Assembly remain primarily stuck on the issue of a financial package from British prime minister David Cameron that would ease the effects of welfare reform.

The prospect of a pre-Christmas talks deal now stands at "no more than 40 per cent", said SDLP Assembly member Alex Attwood as the Minister for Foreign Affairs Charlie Flanagan and the Northern Secretary Theresa Villiers try to coax North's five main parties towards agreement.

While Mr Flanagan said “substantial progress must be made” this week the parties appeared no nearer agreeing a comprehensive deal on issues such as finance and welfare reform, the past, parades and flags and reducing the size of the Executive and Assembly.

The parties are generally agreed that what Mr Cameron last week characterised as a new £1 billion British government financial offering was mainly based on the Executive having extra loan-raising powers, and therefore did not constitute any actual “new money”.

However, a paper on welfare reform presented to the talks by Sinn Fein on Tuesday night was largely rejected by the other parties. Sinn Fein continues to oppose changes such as a household benefits cap of £26,000 and potential reduction in disability living allowance. Civil servants have been asked to cost the Sinn Féin paper.

The Ulster Unionist Party regional development minister Danny Kennedy dismissing the Sinn Féin proposals said "a dose of realism" was required in the negotiations if there were to be any hope of agreement.

In a play on a famous description of a British Labour party 1983 election manifesto he said the Sinn Féin paper was "nothing more than the second longest suicide note in history".

Sinn Féin education minister John O’Dowd refused to speculate on some estimates that his party’s welfare paper would cost an additional £350-£500 million each year. “We make no apology in regards standing up for the ill, the disabled, the low paid in relation to welfare,” he said.

“David Cameron has to come back here, either himself, to come into the talks, or give direction from Downing Street. But there has to be a change of attitude from the British government, there has to be a realistic package brought forward,” added Mr O’Dowd.

SDLP Assembly member Alex Attwood said the chances of a deal currently were no better than "40 per cent". He accused the British government of being "obstinate" and failing to appreciate the special requirements of Northern Ireland.

Mr Flanagan said: “The current window of opportunity to close the gaps on the key outstanding issues and to reach an agreement is rapidly closing.

“ Unless we secure resolution on these issues in the coming days, I fear that the prospects for agreement will be greatly diminished in the new year.”