Taoiseach Leo Varadkar has said the withdrawal agreement is the only Brexit deal on the table.
A special meeting of European leaders took place in Brussels on Sunday, where the remaining 27 leaders endorsed Prime Minister Theresa May's proposals.
Speaking afterwards, Mr Varadkar said people should not be focusing on alternative options.
"Let's not forget what we have here, we have an agreement that took between 18 months and two years to negotiate, it is in several parts, is over 500 pages long and as of today has the support of 28 governments," he said.
"Anyone can have a better deal or an alternative deal in their own minds but an agreement 500 pages long that 28 member states can sign up to nobody has that.
“What's on the table is the only deal that's on the table."
The DUP, which props up the Prime Minister at Parliament, is planning to vote against the proposals amid concern about the future of the Irish border.
On Saturday, DUP Deputy Leader Nigel Dodds called on Theresa May to “bin the backstop”.
Leader Arlene Foster on Sunday called for a Brexit "third way", insisting the choice is not between the current draft agreement and no deal.
"We're not advocating a no deal, we're advocating a better deal," she told the BBC's Andrew Marr Show.
"We want to see the Irish backstop gone. There is no need for the Irish backstop so let's get rid of it."
Arlene Foster added that she is "disappointed with the way this has progressed".
Pressed on whether a defeat of the EU deal in Parliament would spell the end of Ms May's tenure as Prime Minister, the DUP leader said: "That's not a matter for me, that's a matter for her own party."