The Government is scrambling to defuse the controversy caused by Taoiseach Leo Varadkar's warning a hard border would need a "police or army presence" in a no-deal Brexit.
After months of refusals to answer questions on the impact of a no deal, Mr Varadkar's gaffe was viewed as a sign of the panic in Government at the prospect of a looming hard Brexit.
The Government last night denied there were plans to deploy troops to the Border.
The gaffe follows intense scrutiny of contingency planning for a crash-out. Despite denials of any Garda role, it is understood a large number of probationer gardaí are to be sent to the northern region. They will be posted to policing duties in the main population centres, and there they will cover for the release of more experienced personnel for duty at other stations closer to the Border.
In Davos, Switzerland, at the World Economic Forum, Mr Varadkar raised the prospect of the Army and gardaí manning customs posts.
The Taoiseach's clumsy comments sparked criticism from Fianna Fáil leader Micheál Martin. "When the Taoiseach tells an audience in Davos that the Army may have to be sent to the Border, he is contradicting everything we've been told about preparations."
Unionists said Mr Varadkar was "ramping up tensions."
The denials of contingency planning were highlighted this week by Agriculture Minster Michael Creed floundering under questions and State agencies claiming there were no plans for a no-deal scenario.
In the interview, Mr Varadkar said at present the Border was "totally open" but "if things go very wrong it looks like 20 years ago."
He added: "It would involve customs posts, it would involve people in uniform and it may involve the need, for example, for cameras, physical infrastructure, possibly a police presence, or an army presence to back it up."
Mr Varadkar said: "The problem with that in the context of Irish politics and history is those things become targets."
The Government scrambled to clarify Mr Varadkar's remarks. A spokesman said the Taoiseach said the Government was "determined to avoid a no-deal scenario and the consequent risk of a hard border".
He said Mr Varadkar "gave a description of what it used to look like, and the risk of what it could look like in the worst case scenario." He added: "He was not referring to Irish personnel and the Irish Government has no plans to deploy infrastructure or personnel at the border."
Sinn Féin leader Mary Lou McDonald, meanwhile, branded the remarks as "reckless and irresponsible" adding: "They are totally contrary to previous assertions regarding the Government's commitment to the backstop."
Garda Commissioner Drew Harris has moved to deny that plans to deploy 600 gardaí to the Border. But Mr Varadkar's interview in Davos confirmed police and troops could be needed for a hard border.
The Garda did not directly respond to Irish Independent questions about funding or specific contingency plans for a no-deal Brexit border.
A statement repeated Mr Harris's denial that 600 Gardaí are to be moved to the border.
However, the Irish Independent can reveal some details of the contingency planning.
It is understood a large number of probationer Gardaí are to be sent to the Border to help the force cope with the additional workload created.
Probationers are usually divided up between the regions when they are released from the training college in Templemore for on-the-job learning on the streets.
However, a big percentage of the next batch will be deployed in the Garda's northern region, which embraces the Border divisions.
The probationers will be posted to policing duties in the main population centres, as they must be sent to areas with training facilities such as district headquarters, and there they will cover for the release of more experienced personnel for duty at other stations closer to the Border.
The deployment of the probationers is currently being finalised while there are already plans in place to send more armed officers to the Border.
This will be achieved in a two-fold process, transferring more Special Branch personnel to the northern region and setting up a third armed support unit, to be based in Cavan-Monaghan division and augmenting the existing two in Ballyshannon, Co Donegal and Dundalk.
Meanwhile, House of Commons Leader Andrea Leadsom suggested the UK may seek to delay leaving the EU "by a couple of weeks" in order to get Brexit legislation through Parliament,
The prominent Cabinet Brexiteer insisted it would be "feasible" to remain in the bloc for a time after the scheduled exit date of March 29.
Mrs Leadsom's comments came after Chancellor Philip Hammond piled fresh pressure on Theresa May by declining to rule out quitting if the UK goes through with a no-deal Brexit.