The Minister for European Affairs is urging Boris Johnson to "realistically engage" with the EU Commission and leaders this week.
The British Prime Minister is travelling to both Berlin and Paris before this weekend's G7 summit.
In a letter, Mr Johnson reiterated his opposition to the backstop, saying he will not support any withdrawal agreement that includes it.
That was shut down by European Council president Donald Tusk, who said the backstop is there "unless and until an alternative is found."
Minister Helen McEntee says we need to protect our own interests.
"We have always been available to engage with the UK, however, not as has been suggested in terms of a bilateral agreement.
"This is something that has to be agreed between the UK and the EU and us as memebrs of the European Union because of couse we are not leaving.
"We cannot allow the situation where a decision by another country will take us either out of the EU or the single market or the customs union, or impact our country in such a negative way."
Ms McEntee said that technology or trusted trader schemes can not replace the backstop.
She said they "have been looked at by both the UK and the EU" but added that the backstop is "the one way that we can deal with all of these committments that have been made."
Earlier today, Tánaiste Simon Coveney echoed Ms McEntee's words, saying Ireland “cannot do a side deal” with the UK.
“That’s not going to work," he told RTÉ radio’s Today with Miriam O’Callaghan show.
"Our preparations have to be with the European Union, we are going to stay in the European Union, we have to work with our European partners if we don’t have a partner in the UK government.”
