A no deal Brexit crisis could cost the Irish tourism industry as much as €390m - a prediction that is €130m worse than previously feared and could see thousands of people lose their jobs.
Fáilte Ireland chief executive Paul Kelly issued the dire warning after Taoiseach Leo Varadkar's backstop climb-down ratcheted up speculation over whether a deal could be inching within reach.
Asked at the Oireachtas transport and tourism committee how damaging a worst case scenario no deal Brexit could be, Mr Kelly said such a situation will pose the Irish tourism industry severe problems.
The Fáilte Ireland chief executive said: "The Tourism Industry Council have published one scenario specifically looking at UK visitors, and they've made the estimate of €260m as a revenue impact of the industry.
"We've looked at alternative scenarios. They're only scenarios, and one would have placed the impact as €390m based on modelling of the ash cloud and foot and mouth [crises].
"They are only scenarios, and of course it will depend on aviation and open sky [in relation to Brexit]. But there's no doubt again it would be a very significant impact."
Mr Kelly said if a no deal situation occurs the tourism industry will need "in the region of €20m in incremental extra funding every year".
He added that the pre-budget 9% VAT rate on hotels "would have helped to continue to fuel the growth of the sector" had it been retained, and that job losses are likely as a direct result of a no-deal Brexit.
Asked about Brexit "pressure points", Tourism Ireland chief executive Niall Gibbons said that "if the British tourists decide to travel in less numbers, that's going to have an impact in Ireland".
Meanwhile, police chiefs on both sides of the border have pledged to find a way to continue co-operation whatever Brexit deal emerges.
Garda Commissioner Drew Harris and PSNI Deputy Chief Constable Stephen Martin stressed the importance of maintaining partnership arrangements currently facilitated by their respective jurisdictions' membership of the EU.
They warned against the consequences of a hard border on the island, with Mr Harris cautioning it would create an "emotional driver" that violent dissident republicans would seek to exploit.