The UK government has asked the Queen to suspend Parliament just days after MPs return to work in September - and only a few weeks before the Brexit deadline.
Boris Johnson said a Queen's Speech would take place after the suspension, on 14 October, to outline his "very exciting agenda".
But it means the time MPs have to pass laws to stop a no-deal Brexit on 31 October would be cut, reports BBC.
House of Commons Speaker John Bercow said it was a "constitutional outrage".
The speaker, who does not traditionally comment on political announcements, continued: "However it is dressed up, it is blindingly obvious that the purpose of [suspending Parliament] now would be to stop [MPs] debating Brexit and performing its duty in shaping a course for the country."
It would be "an offence against the democratic process and the rights of Parliamentarians as the people's elected representatives", he added.
Labour leader Jeremy Corbyn said he was "appalled at the recklessness of Johnson's government, which talks about sovereignty and yet is seeking to suspend Parliament to avoid scrutiny of its plans for a reckless no-deal Brexit".
He added: "This is an outrage and a threat to our democracy."
The PM, though, said suggestions the suspension was motivated by a desire to force through a no deal were "completely untrue".
He said he did not want to wait until after Brexit "before getting on with our plans to take this country forward", and insisted there would still be "ample time" for MPs to debate the UK's departure.
"We need new legislation. We've got to be bringing forward new and important bills and that's why we are going to have a Queen's Speech," he added.
The idea of shutting down Parliament - known as prorogation - is highly controversial because opponents say it would stop MPs being able to play their full democratic part in the Brexit process.
A number of high profile figures, including former Prime Minister John Major, have threatened to go to the courts to stop it, and a legal challenge led by the SNP's justice spokeswoman, Joanna Cherry, is already working its way through the Scottish courts.
Jonny Dymond, royal correspondent of BBC, said it was established precedent to prorogue Parliament before a Queen's Speech, albeit generally more briefly, and rarely, if ever, at such a constitutionally charged time.
He said it was "Her Majesty's Government" in name only and it was her role, constitutionally, to take the advice of her ministers, so she would prorogue Parliament if asked to.
BDST: 1757 HRS, AUG 28, 2019
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