Bill Wolsey said the area was already playing second fiddle to Dublin and tourists would not bother coming if it became more bureaucratic.
He opens a new £7 million four-star hotel - Bullitt - in the heart of Belfast’s Cathedral Quarter at the weekend.
Mr Wolsey helped lead the campaign for Remain before the referendum and had predicted minimal growth or recession before the poll.
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He said: “No matter how bad things get we are very good operators and we have been successful in some of the darkest days of the Troubles here and nothing can be that bad.
“But this has been a self-inflicted wound, which is thoroughly depressing.”
Movement of people between the EU and UK is one of the key areas up for negotiation when talks are triggered next year.
Mr Wolsey said: “If visas are introduced at all for the UK I think that would be hugely detrimental to our business because at the minute we play second fiddle to Dublin and if a tourist has to do one extra thing they will not do it.”
He said listing foreign workers was a crazy idea from Westminster.
“That alone shows the state of disarray that the Government are in, it is worrying on a whole range of levels.”
He added: “The dangers that would hit England, Scotland and Wales I think could be much more pronounced here in Northern Ireland.”
He opens Bullitt this weekend.
“We have entered the sleepy corporate world of four-star hotels.
“Think man in loafers, pink jumper tied around his neck.”
He said they were targeting the relatively affluent, aged 25 to 45.
“You have something which hopefully says something about people’s aspirations, which is representative of where they are.”
Guests ascending by lift to one of the 43 “dinky”, “comfy” or “roomy” rooms will hear the voice of music critic and broadcaster, Joe Lindsay, “This is the second floor, so it is’, adding, “doors are opening, so they are”.
The rooms were designed by the hotelier and other senior staff.
He said: “They have the best beds money can buy, interestingly designed room with air conditioning.
“We have one of the best locations in Belfast, right in the heart of the Cathedral Quarter.”
Rooms cost between £120 and £275 and the hotel opens on Saturday.