"We have got to work together, In order to resolve those issues and get it right for our people, it is necessary now to move on to the second stage of the negotiations which really entail so numerous questions that are bound up with the border issue", he said at a press conference in Iveagh House.
And he stressed that many of Europe's countries do want us to move on with Brexit talks.
Irish Prime Minister Leo Varadkar meanwhile struck a firm line, insisting there had to be progress on Dublin's demands that Brexit should create no "hard border" between British- ruled Northern Ireland and European Union member Ireland.
"We all hope that we can decide on the next phase but we still have some way to go", he said.
It is the obvious solution as no-one wants physical border controls, the former chancellor and now Conservative "rebel" told BBC NI's The View.
Britain and Ireland clashed over Brexit on Friday with Dublin saying it was not ready to allow the talks to move on to the second phase next month and London ruling out the much longer transitional period preferred by its neighbour.
Rival US and Russian resolutions defeated on Syria weapons
It was the 10th time that Russian Federation has used its veto power to stop council action that targeted its ally Syria. Only Russia, China, Bolivia and Kazakhstan voted in favor while seven council members voted against and four abstained.
"The border problem in Northern Ireland, the supreme importance of keeping the settlement in place, retaining peace in Northern Ireland is probably the single biggest, most important reason why it would be preferable for the United Kingdom as a whole to stay in the single market and the customs union", he said. "Sometimes it doesn't seem like they've thought all this through", he said, of May's government.
British foreign secretary Boris Johnson has refused to guarantee there will be no border along the North with Brexit and says the issue will instead be negotiated in phase two of the talks, writes Juno McEnroe.
Johnson said moving the talks onto the next stage would help to resolve the border issue as numerous questions around it were bound up with Britain's future customs arrangement with the European Union.
The EU's Donald Tusk will meet Theresa May this morning for crunch talks ahead of the bloc's council meeting next month. "We have very serious issues, particularly around the border, that need more clarity".
"The clock is ticking". "I hope that we will be able to come to an agreement as far as the divorce is concerned in the December (EU) council but work has still to be done".