The SDLP leader, Dr Alasdair McDonnell has told his party's annual conference today that Sinn Féin and the DUP were parties of poor government, bad politics and no results.
He is seeking to re-establish the SDLP as the main nationalist party in advance of next year's European Elections.
Earlier, he called for a "prosperity process" similar to American aid which rebuilt Europe following the ravages of the Second World War in Northern Ireland.
The mini Marshall Plan should underpin the peace process and Good Friday Agreement and tackle problems such as youth unemployment and emigration, SDLP leader Alasdair McDonnell said.
Mr McDonnell argued that hopes of an economic boost at the time of the signing of the 1998 peace accord had been dashed.
"I am calling on the OFMDFM, the Executive and the British and Irish Governments, even at this late stage, to do all that is necessary to establish a meaningful prosperity process as a matter of urgency.
"We need a prosperity process that will underpin the peace process and lay the foundations to create the well-paid jobs that would banish the specter of youth unemployment and emigration that has brought so much heartbreak to our communities."
The Marshall Plan, named after the US general who conceived the idea, used American money to rebuild a Europe devastated by the Second World War.
Unemployment is still significant in Northern Ireland, with 22% of young people out of work.
Despite this, Northern Ireland is second only to London in the UK as the top destination for inward investment.
Recently, British Prime Minister David Cameron led an investment conference for Northern Ireland following the G8 meeting of world economic powers in Co Fermanagh.
Mr McDonnell told his party conference in Armagh a formal prosperity process was needed, pursued with the same ambition and determination as the peace process.
"Indeed, 15 years ago many of us expected a prosperity process; a mini Marshall Plan; to be constructed to underpin the peace process and the Good Friday Agreement.
"There were promises - hopes were raised; and hopes were dashed," he added.
Gilmore addresses SDLP conference
Elsewhere, Tánaiste Eamon Gilmore said that the hope which followed the Good Friday Agreement should not be lost through one-dimensional politics.
Mr Gilmore urged politicians to make progress in north/south relations and the Richard Haass talks on parades, flags and dealing with the legacy of the past.
He called for renewed friendship and trust as well as broader mobilisation by members of the community to create a more reconciled and prosperous future.
"Making progress, whether in the context of north-south relations or in the context of the Panel of Parties talks, relies on the maintenance, building and renewing of trust and friendship in the totality of relationships across these islands," he told delegates at the SDLP party conference in Armagh.
"One-dimensional politics does not fit with the concept of the Good Friday Agreement, which requires all of us, the SDLP, the government and others to all work together.
"We cannot risk letting the germ of hope, opportunity and ambition which has taken hold in so many communities be left to go to seed."
Mr Gilmore's address focused on boosting the economy - including tackling high levels of youth unemployment and better cross-border cooperation - as well as the need for reconciliation.
He said people needed to realise the potential of the 1998 Agreement and all its parts, including a bill of rights, a civic forum, greater participation of women in political life, integrated education and shared housing.
"We cannot be selectively blind to those parts we find difficult. When we pick and choose, the balance and integrity of the whole is picked apart," Mr Gilmore said.
"We need to recall and renew the hope, ambition and political leadership which made the Agreement possible in order to deal with the challenges which we are currently facing, including in the context of the ongoing Haass process."
The Labour Party leader acknowledged that these are substantial and ambitious undertakings which can only be achieved through close and honest cooperation between the British and Irish Governments and parties in Northern Ireland.
"It also requires a broader mobilisation of opinion across business, community, faith and other sectors to demand real and consistent investment by all in a more reconciled and prosperous future," he added.
He commended the SDLP's approach to the Haass talks.
"This is a time for hope and the ambition to see further progress made towards advancing reconciliation and the creation of a truly reconciled society."