Dr Richard Haass reacted after First Minister Peter Robinson urged parties to move the process forward after marathon negotiations on parades, flags and the past ended without a deal on New Year's Eve.
It came after the DUP and Ulster Unionists both indicated they had major difficulties with a number of proposals drawn up by the Haass team.
"We must not lose the momentum and we each should take care that areas of agreement are not allowed to unravel," the DUP leader said earlier this week.
Mr Robinson said he supported the proposal by Dr Haass to now create a working group made up of representatives of the DUP, Sinn Féin, UUP, SDLP and Alliance.
"I will recommend to my party colleagues that they support the suggestion made by Dr Haass that a "working group" be established to see how agreed elements can be taken forward while seeking to resolve areas where disagreement remains," Mr Robinson added.
Dr Haass welcomed Mr Robinson's assessment that the negotiations were not a failure, tweeting out details of UTV's report of the DUP leader's intervention.
He exhorted the five main parties to "act where consensus" exists.
SDLP leader Alasdair McDonnell has also called for the creation of the working group after the party endorsed the Haass proposals following meetings on Thursday night.
"The SDLP Parliamentary Assembly Group and Executive respectively met tonight," Mr McDonnell said.
"The SDLP believe that the opportunity of this moment needs to be grasped. I will write to the First Minister and deputy First Minister to urge that a five party working group is immediately convened.
"Its purpose to is work up the implementation of the Haass O'Sullivan proposals, plan the legislation that is necessary and bring resolution to issues that remain."
Earlier Sinn Féin President Gerry Adams warned the other parties not to fudge their response to the Haass document.
The Louth TD said his party "stretched itself" during the marathon sessions.
Sinn Féin's ruling executive will meet next week to discuss the fall-out from the process.
Mr Adams said: "Sinn Féin has stretched ourselves in these negotiations and we are up for this challenge.
"The issues of parades, flags and emblems and the legacy of the past are not going away.
"There is an onus on the Irish and British governments and all of the parties to maintain the momentum that was created and to build on this progress.
"Sinn Féin's negotiating team believes that the Haass proposals provide the basis for an agreement between all of the parties and we will be recommending it to Ard Chomhairle," Mr Adams said.
The Sinn Féin Ard Chomhairle will be meeting on 11 January.
Meanwhile the Ulster Unionist Party has announced that its executive body will meet on Monday to discuss the Haass process.
Party leader Mike Nesbitt said: "This was an initiative from Peter Robinson and Martin McGuinness, and it falls to them to outline how they see this process moving forward."
Mr Nesbitt also blamed Alliance after the talks collapsed.
"The problem is that Alliance have opened the Pandora's Box called cherry-picking and that is the one thing Richard Haass wanted to avoid. He wanted the parties to look at the last document and either endorse it or take it away to their executive or reject it in full."
Alliance negotiator Chris Lyttle has rubbished his comments.
"The idea that Alliance is a problem in this process is absurd and dishonest. The key task now is for all parties to work together with the public to achieve timely and actual progress on all three issues for the common good of our whole community," he said.
Significant progress was made during marathon talks, particularly in the area of dealing with the past after seven drafts of the proposed document were issued.
The final draft also included the creation of a new body to look into all unsolved cases, called the Historical Investigations Unit.
It also proposed a new Office for Parades and Protests.
But when it came to flags there was no consensus.