Martin McGuinness and Peter Robinson have spent time together in what is being described as a "bonding session".
The aim of the exercise was to restore their strained relationship which is at its worst since 2007.
They are even seen together in public less often than before.
The agenda at their meeting featured thorny political issues which have divided them.
These include the long-delayed Cohesion Sharing and Integration (CSI) strategy and welfare reform, where Sinn Fein threatened to raise blocking petitions of concern.
Normally the two men spend most of Tuesday in Parliament Buildings at the Assembly. This time they broke with tradition and headed for their offices in Stormont Castle with a few aides.
"This does not mean an immediate deal on issues like CSI and welfare reform but it is an important first step," a source said.
He added: "they both realised that the public perception that they weren't getting on, that it was playing badly. They used this meeting as a springboard to try and to resolve the other deeper issues. They basically spent a full day in a big clear-the-air session.
"The first thing they had to do was deal with all the poisonous stuff that has been happening the last few days," he stated.
Last Friday Martin McGuinness rounded on the DUP at his party conference, accusing them of not wanting to be in government with him.
"It was about parity of esteem," a Sinn Fein source said.
Then the Sinn Fein justice spokesman Gerry Kelly questioned the impartiality of the police and launched an attack on Chief Constable Matt Baggott.
The DUP reacted strongly to parts of a Belfast Telegraph survey of delegates at the Sinn Fein Ard Fheis which found that 72% agreed with Martin McGuinness's statement that the dissidents were traitors to Ireland while 26% believed an armed campaign was justified.
Other findings, showing openness to unionist sensitivities, did not register with the DUP.
On Monday they demanded assurances from Mitchel McLaughlin of Sinn Fein, who was standing in for the post of Deputy Speaker, that he backed law and order and opposed dissident violence.
After these were forthcoming, two DUP ministers, Arlene Foster and Edwin Poots, accused Sinn Fein of double standards.
Realising the dangers of escalating the dispute, Mr Robinson was more restrained in his comments.
He praised Mr McGuinness's position on policing and the dissidents and said he believed Mr McLaughlin would support it.
It is understood the two men will continue to meet throughout the week. They also hope to make more joint public appearances.
Last night, in a show of unity, they issued a joint statement expressing sympathy with those injured of bereaved in the Boston Marathon bombing.
"Our thoughts and prayers are with the friends and families of all those killed and injured in this horrific turn of events," it said.
Relations between the DUP and Sinn Fein have been deteriorating for months. Things came to a head at the weekend over comments made at the Sinn Fein Ard Fheis by Gerry Kelly and Martin McGuinness. On Monday the DUP reacted angrily in the Assembly to the findings of a Belfast Telegraph survey which found that many delegates at the Sinn Fein conference has some sympathy for the dissidents and scepticism about the impartiality of the police.