Shadow Brexit secretary Sir Keir Starmer said Mr Johnson's speech had revealed the Government’s intention to “casually cast aside” rights and protections when the UK leaves the European Union.
The Confederation of British Industry insisted that firms did not want a “bonfire of regulations”.
Sir Keir said Mr Johnson’s approach would “further divide the country” and put jobs and living standards at risk.
He said: “This speech underlined the Government’s real intentions; a Brexit of deregulation, where rights and protections are casually cast aside and where the benefits of the single market and the customs union are ignored.
“Nobody will be fooled or reassured by the Foreign Secretary’s empty rhetoric.
“His insistence on deregulating our economy is the opposite of what businesses and trade unions want to hear.”
TUC general secretary Frances O’Grady said: “People have learned not to trust Boris Johnson.
“Instead of calming the worries of working people, he fuelled fears that he believes essential workplace rights are ‘intolerable’.
“When he says ‘regulatory divergence’ he means scrapping hard-won rights to paid holidays, equal pay and safety at work. And if that’s his vision, he’s never going to unite the nation behind it.”
John Foster, the CBI’s director of campaigns, said businesses were committed to making Brexit a success, but “evidence, not ideology, should guide the UK’s thinking on a close future relationship with the EU”.
He said: “Businesses aren’t looking for a bonfire of regulation – quite the opposite – our aerospace, automotive and chemical sectors, to name a few, all have highly integrated European supply chains that benefit from consistent regulation.
“And securing alignment of data rules is vital to protect the thousands of innovative businesses that make up the UK’s £240 billion data economy.”
Technology industry body techUK’s chief executive Antony Walker said: “We do not make the UK more attractive to the rest of the world by putting barriers in the way of trade with our biggest market.
“Whilst there may be areas where the UK wants to diverge from EU rules in the future, these are likely to be limited as the gains from divergence would have to outweigh the very significant benefits of having alignment with our closest trading partner.”
Liberal Democrat Brexit spokesman Tom Brake said: “Boris Johnson is completely deluded about Brexit.
“This speech wasn’t about the most important issue facing our country right now, this was about Boris’ ambitions to become the next prime minister, and it probably wasn't much help on that front either.”
But Richard Tice, co-chairman of the pro-Brexit Leave Means Leave group, welcomed the “optimistic vision” set out by Mr Johnson.
He said: “The opportunities outside of the EU are immense, in terms of trade and the economy as well as by taking back control of our laws, borders and money.
“To achieve this, the Government must not allow us to be handcuffed to EU regulations and bureaucracy after we leave in March 2019.”