Taoiseach Leo Varadkar has told the Dáil that the EU, including Ireland, will continue to search for a positive outcome in relation to Brexit until the "last minute".
He reiterated that he thinks there is a pathway to a possible Brexit agreement.
However, he said the question remains about whether the negotiations can bridge the remaining gaps before tomorrow's council meeting.
Speaking in the Dáil in advance of the European Council in Brussels, he reiterated that following his meeting with British Prime Minister Boris Johnson last week he is convinced that all parties want agreement on Brexit.
He said a deal was possible but there are issues to be resolved, including consent and democracy, and ensuring that any long-term arrangements for Northern Ireland has the consent of the people.
He said there must be no customs border between Northern Ireland and the Republic of Ireland and no tariffs on trade.
The Taoiseach said the agreement must avoid a hard border and it must protect the single market.
Fianna Fáil Leader Micheál Martin said the debate was being held in a vacuum and was reliant on "incomplete briefings" that the Government had provided to the media.
The Taoiseach's planned briefing of opposition party leaders is now not expected to take place tonight.
Some party leaders had thought there would be a briefing in the Sycamore Room in Government Buildings at 8.15 tonight but the meeting did not take place.
Government Ministers had also been on standby throughout the evening in case of an emergency Cabinet meeting, however a number of them have now left Leinster House and returned home.
Earlier, at a Department of Agriculture conference Mr Varadkar said he was hopeful that a deal on Brexit could be done, but he warned that it may not happen.
He said he spoke to Mr Johnson by telephone this morning and also to the EU Commission.
Mr Varadkar said everyone was trying to work towards a deal this week, in time for a scheduled summit of EU leaders, and, for the House of Commons to consider the matter on Saturday.
However, he told the conference that if a deal was not agreed this week, then there was a possibility of a further EU summit being held before 31 October if needed.
Mr Varadkar said although time was running short on reaching a deal, he was confident that the objectives of the Government relating to Brexit could be achieved.
He said the Government wanted to avoid a hard border, protect the Good Friday Agreement and ensure that the all-island economy continued to "thrive and prosper", and to protect the integrity of the single market.
Mr Varadkar said in the meantime, regardless of the prices to reach a deal, the Government must continue with its preparations for a possible no-deal scenario. He said the Government must prepare for what he called, "the worst-case scenario".
Demonstrations are taking place at dozens of border crossing points this evening, as efforts continue to try reach a deal on Brexit.
People from both sides of the border are expected to gather at 38 locations along the border.
The Border Communities Against Brexit Group have organised the demonstrations.
They say they want to highlight their opposition to a no-deal Brexit, ahead of the EU summit tomorrow.
- Latest Brexit stories
- Barnier 'optimistic' of Brexit deal today
- Fresh warning over post-Brexit US-UK trade deal
Additional reporting Micheál Lehane