Update 9.04am: The Sinn Féin Leader says she was concerned to hear that the Taoiseach was open to a review of the backstop.
Mary Lou McDonald has cautioned Leo Varadkar not to lose his nerve when it comes to Brexit negotiations.
The backstop is a safety net-type proposal designed to prevent a hard border after Northern Ireland and the rest of the UK leaves the European Union next year.
Yesterday, the Taoiseach said he would be willing to consider proposals for a review clause in relation to the Irish border safety net.
However he said the UK can not have the option to cancel the "no hard border" guarantee of its own accord.
Deputy McDonald says she will be seeking clarification today.
"When I heard that he was open to a review, it did concern me," said Ms McDonald.
"It concerns me yet, I hope we will get clarification from him (Mr Varadkar) on the floor of the Dáil.
"The protections that we need for Ireland must be enduring. They can't be temporary and they are not matters to be up for review."
Meanwhile, Minister for European Affairs Helen McEntee disagrees that the Government is losing its nerve when it comes to Brexit.
"I wouldn't agree that things are changing, that we're starting to get nervous," Ms McEntee.
"What we're saying is that there needs to be, or there can be - and we're very open to the possibility - that there could be a mechanism by which both the EU and the UK know when the backstop is no longer necessary.
"So this does not change the backstop in itself."
- Digital Desk
Earlier: No-deal Brexit in danger of becoming frightening reality - Howlin
Labour Party leader Brendan Howlin says the prospect of a no-deal Brexit is in danger of becoming a frightening reality.
British Prime Minister Theresa May is preparing to brief her Cabinet today on the latest stage of the negotiations.
There are conflicting reports about whether a Brexit deal has been finalised.
Brendan Howlin is calling for clarity from the Taoiseach.
"The stakes are so high for all the people of all Ireland," said Mr Howlin.
"I hope during the Dáil debates this week the Taoiseach will give that clarity and that Simon Coveney will be very clear to all his colleagues across the Oireachtas exactly what is happening.
"But more importantly what is the bottom line for the Irish Government that we won't allow ourselves to be either out-manoeuvred or bullied into a position that is not in the interests of the Irish people."
Later today, Ms May will face the UK Cabinet after the Government insisted it would not accept any unilateral UK ability to end a Brexit backstop agreement on the Irish border.
After days of speculation a deal on the Irish border issue was imminent, Leo Varadkar used a telephone call with Mrs May on Monday to reject her calls for any agreement to include a mechanism to bring an end to the backstop – designed to ensure there is no hard border in Ireland if the UK and EU fail to reach a broader trade deal.
However, Mr Varadkar’s spokesman said the Taoiseach indicated he was ready to consider proposals for a review mechanism, though only if it was clear that the arrangement could not be ditched unilaterally by either side.
The backstop issue has become the major obstacle to agreement on the UK’s withdrawal from the European Union, due to take place on March 29, 2019.
- Digital Desk & PA