Tanaiste Simon Coveney has denied he and Taoiseach Leo Varadkar were at odds on the issue of the Irish backstop, as alleged by former British Brexit Secretary Dominic Rabb.
Mr Raab on Sunday said that Mr Coveney did not rule out an exit mechanism from the backstop when they met.
Speaking on the Andrew Marr Show on the BBC, Mr Raab said that an exit mechanism was ruled out by the Taoiseach Leo Varadkar, who he described as "less moderate" than Simon Coveney.
He added: "They have taken this deeply political view on the backstop, which has got nothing to do with the realities of solving a return to the hard border and now we need to make sure that there is a ladder for them to climb down."
But this drew a response from Mr Coveney who on Twitter said: “For the record, Taoiseach & I have always been on the same page on Brexit & we remain united & focused on protecting Ireland. That includes continued support for the EU/UK agreed on WA in full, including the Backstop as negotiated.”
For the record, Taoiseach & I have always been on the same page on #Brexit & we remain united & focused on protecting Ireland. That includes continued support for the EU/UK agreed WA in full, including the Backstop as negotiated. @RTENewsNow https://t.co/ljmSBtvuNz— Simon Coveney (@simoncoveney) January 20, 2019
Government Chief Whip Sean Kyne did not dismiss reports from the UK media that Mrs May is about to seek a bilateral treaty with Ireland in a bid to overcome the backstop impasse in the House of Commons ahead of the March 29 deadline.
Speaking on RTE's The Week in Politics, Mr Kyne said any proposal from Mrs May would need to have the backing of MPs. He also said the Irish Government would wait to see the full details of what she is proposing before giving a formal reply.
He said Mrs May would have to relax some of her red lines before the EU and Ireland could explore any options.
The Government has held fast to the backstop concept as the bare minimum in the post Brexit scenario.
However, the chances of a no-deal Brexit have increased following Mrs May's humiliating defeat in the House of Commons this week.