A no-deal Brexit would significantly impact and change the economics of bringing a car from the UK into Ireland.
That is according to the Chairman of the Revenue Commissioners, who is appearing before the Oireachtas Finance Committee.
Niall Cody said if the UK leaves the EU those who buy cars in the UK will be liable for VRT and VAT as normal.
However, he added that they will also be liable for a customs tariff which, in the event of a no deal, will be 20% on a diesel car and 10% on petrol.
He said it would significantly change the cost of bringing in a car into the country from the UK.
Mr Cody said that if Britain leaves the EU with no-deal, VAT at the point of entry will more than double.
Considering Revenue took in €1.5bn in VAT last year, Mr Cody told the committee that if the UK becomes a third country the figure would be significant.
When asked by Fine Gael Senator Kieran O'Donnell for an estimation, the Mr Cody said having taken a preliminary look at the figures, at the lower end of the scale it would bring in an additional €1.5bn.
Earlier, Mr Cody said Revenue had identified two key trader groupings expected to be significantly impacted by Brexit.
Large economic operators who trade with the UK and logistics companies or freight forwarders will be most affected, he said.
In his opening statement, Mr Cody said Revenue wrote to these traders last November, highlighting the Brexit-related supports available to them.
He said Revenue has "accelerated and expanded" recruitment and training schedules in preparation for a no-deal Brexit.
"We are on track to have over 400 (of 600) additional staff in place by the end of March; we have re-assigned serving staff, are preparing for any necessary further redeployments on a temporary basis; and will have the balancing complement of additional staff recruited by the end of 2019," he said
Mr Cody said the central case for the recruitment of 600 staff was based on the Withdrawal Agreement, the transition period and the full implementation of the process from January 2021.
He said in the event of a no-deal scenario, those numbers will have to be pulled forward as soon as possible this year, but 600 staff will remain the number, even there is a no-deal Brexit.
Mr Cody was answering a question from Fianna Fáil TD Michael McGrath if he had estimated staffing for a no-deal Brexit.
Mr Cody has also said that Revenue was working with the Department of Agriculture, Food and the Marine and others to coordinate activities, for optimal trade facilitation at Ireland's ports.
On infrastructure, Mr Cody said an inter-departmental group chaired by Revenue considered the adequacy of port and airport infrastructure and facilities, post-Brexit.
He said the Office of Public Works, which is responsible for the delivery of the required infrastructure, is now actively engaged with relevant stakeholders with a view to ensuring that needs are met.
In a no-deal scenario, the free circulation and movement of goods between EU Member States and the UK will end, he said, noting that the Government has made clear that its overriding objective is to avoid a hard border on the island of Ireland.
"Revenue is not planning for customs posts", he said.
Revenue has given a break down of custom official figures at ports & airports here post #Brexit . 130 will be based at Dublin Port, 80 in Dublin Airport and 30 in Rosslare— Ailbhe Conneely (@AilbheConneely) January 24, 2019
He said there would have to be a declaration process, which was why Revenue had concentrated on scaling up its systems to allow traders in the Republic make a declaration.
Revenue is looking at goods entries being presented online and not at Revenue offices, he said, and the process will be online.
However, in relation to 45,000 small traders with import transactions, Mr Cody said the most efficient way to deal with those would be through a customs clearance agent, which he said would cost money.
"The Government has indicated that in the event of no deal, it will engage in intensive discussions with the EU Commission and our EU partners and Revenue will provide whatever technical expertise and assistance may be required during this process," he added.
Meanwhile, Garda Commissioner Drew Harris has described media reports on the deployment of 600 gardaí to border areas as "entirely incorrect".
In a statement, he said: "Reports of 600 gardaí to be moved to the border are entirely incorrect. I have not discussed this matter, neither have I considered this proposal.
"The increasing deployment of gardaí to all policing regions including the Northern Region is commensurate with a growing organisation.
"We continue to prepare for Brexit in line with Government policy."