The House of Commons has returned in “exceptional and unprecedented” circumstances, the Speaker says.
Sir Lindsay Hoyle opened the first day back since the Easter recess amid the coronavirus crisis.
A motion allowing a “hybrid” Parliament, with some MPs in the chamber and others connected via video link, is expected to be approved.
Leader of the House, Jacob Rees-Mogg, said the Commons could not let “perfect be the enemy of the good”.
Some MPs were present in the Chamber – sitting socially distances from each other – and after the motion is approved, the number of members allowed inside is expected to be limited to 50.
Sir Lindsay led a rehearsal on Monday in which ministers faced questions via video link.
Screens have been installed in the chamber to allow MPs to speak remotely while the limited number attending in person will be signposted where to sit.
The new practices will initially operate until 12 May although could remain in place for longer.
They are part of a raft of changes designed to allow Parliament to continue to operate during the coronavirus outbreak, including reduced sitting hours, virtual committee meetings and strict social distancing measures within the Palace of Westminster.
The measures will then come into force on Wednesday.
It is hoped the Zoom video-conferencing tool will allow up to 120 MPs to respond to ministerial statements and urgent questions while also allowing ministers not able to attend in person to participate.
Prayer cards normally used to reserve places for MPs on the Commons benches have been replaced by green and red symbols indicating where they should and should not sit in order to keep the recommended six feet apart.
Business on Tuesday and Wednesday is likely to focus exclusively on the government’s response to the pandemic.
While the new system will not initially be used for debating legislation – which will be confined to those actually in the chamber – MPs have called for it to be extended to other forms of parliamentary business.
Sir Lindsay told BBC Radio 4’s Today programme he viewed the new arrangements as a “starting point, not the end,” and expected votes on legislation “will come”.
He urged MPs to participate from home as much as possible, pledging those in the chamber would be at “no advantage” to their colleagues working remotely.
Meanwhile, Downing Street has confirmed that the prime minister is continuing his recovery at Chequers.
According to the prime minister’s official spokesman, Mr Johnson is expected to hold an audience with the Queen at some point this week.
The telephone conversation will be the first between Mr Johnson and Her Majesty for three weeks.
The Prime Minister is also due to speak to US President Donald Trump later on Tuesday.
The spokesman said that while the PM is not “formally doing government work”, he has been “receiving updates from No 10 on the coronavirus response and has spoken with Dominic Raab and senior members of his team”. Mr Raab, the foreign secretary, is deputising for the PM while he recovers.
It will be a different universe – there won’t be the roar of the Commons chamber and crammed green benches for big moments like Prime Minister’s Questions.
There will be no votes for now, although they are looking at how they might be able to do that electronically in the future.
MPs working from home have been told still to dress smartly, so there’ll be no glimpses of MPs taking part in their pyjamas from home.
This is a limited step, but a very important one. But it’s like a sort of digital toe being dipped in rather than diving into anything like business as usual.
Remote working will also be in operation in the House of Lords, where some non-legislative debates will be taking place virtually after guidance was changed by senior peers.
These will only be broadcast from early May, while debates on laws will initially continue in the chamber with the “expectation of limited participation”.
Lord Fowler, who chairs business in the Lords, said a decision had not yet been made on whether peers working remotely will be able to claim their normal daily allowance.
He told the Today programme the issue would be examined “with an open mind” at a meeting next Monday.
The Commons Procedure Committee – which looks at the ways MPs conduct business – said it was right Sir Lindsay had asked the authorities to examine whether remote digital voting could be introduced for a “strictly time-limited period”.
In a report welcoming the wider changes proposed by the Speaker, it said remote voting would be a “fundamental change to the way that the House has conducted its business”.
“We will wish to give detailed consideration to any system developed to supplement or to replace existing mechanisms for divisions, where such a system will which enable absentee voting,” it said.
The committee, chaired by ex-Northern Ireland Secretary Karen Bradley, also expressed concerns about the ability of MPs to hold the government to account.
The government announced on Friday that Parliament would only be sitting for three days a week until future notice, with Thursday and Friday sittings axed.
MPs have now called for limits on written questions to be put to ministers to be relaxed, to allow more scrutiny.