Jeremy Corbyn has accused Theresa May of focusing on health tourism in order to "distract" from the issue of NHS funding.
The Labour leader said plans to make patients in England show their passports before receiving treatment on the NHS were ultimately "divisive and impractical".
"The last census showed that 9.5 million people in this country don't have passports," Mr Corbyn during Prime Minister's Questions.
"Rather than distracting people with divisive and impractical policies, could you provide the NHS and social care with the money that it needs to care for the people who need the support?"
The Department of Health is examining whether patients should have to show two forms of ID to access some elements of NHS care.
Chris Wormald, permanent secretary at the Department of Health, told the Public Accounts Committee some trusts were triallling the proposal.
He said: "There are individual trusts like Peterborough who are doing that, who are reporting that it makes a big difference and there you are saying 'please come with two forms of identity, your passport and your address' and they use that to check whether people are eligible or not."
He said the Department was looking at "whether more trusts should be going down the route, that some trusts within London and elsewhere have gone on, forcing people to prove identity", adding: "And where that is proportionate? [Whether in just some places] or whether you want to apply it to the whole country. Those are the questions that we are looking at."
Citing National Audit Office estimates, Mr Corbyn said the cost of health tourism was "over 100 times less than the £22 billion of cuts the NHS is facing from this Government".
UK news in pictures
UK news in pictures
1/17 22 June 2017
Cosplay fans (L-R) George Massingham, Abbey Forbes and Karolina Goralik travel by tube dressed in Harry Potter themed costumes, after a visit to one the literary franchise's movie filming locations at Leadenhall Market in London, Britain
2/17 22 June 2017
Racegoers cheer on their horse on Ladies Day at the Royal Ascot horse racing meet, in Ascot, west of London
3/17 21 June 2017
A reveller walks among the tipi tents at the Glastonbury Festival of Music and Performing Arts on Worthy Farm near the village of Pilton in Somerset, South West England
4/17 20 June 2017
A police officer lays some flowers passed over by a member of the public, close to Finsbury Park Mosque in north London, after one man died and eight people were taken to hospital and a person arrested after a rental van struck pedestrian
The Borough Market bell is seen in Borough Market in central London following its re-opening after the June 3 terror attack
Two women embrace in Borough Market, which officially re-opens today following the recent attack, in central London
Mayor of London Sadiq Khan attends the re-opening of Borough market in central London following the June 3 terror attack
People walk through Borough Market in central London following its re-opening after the June 3 terror attack
News Corp CEO Rupert Murdoch, with one of his daughters, visit Borough Market, which officially re-opened today following the recent attack
A woman reacts in front of a wall of messages in Borough Market, which officially re-opened today following the recent attack, in central London
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Richard Arnold, Roy Larner, Piers Morgan and Susanna Reid on 'Good Morning Britain'
14/17 11 June 2017
England players celebrate after defeating Venezuela 1-0 to win the final of the FIFA U-20 World Cup Korea 2017 at Suwon World Cup Stadium in Suwon, South Korea
15/17 11 June 2017
England players celebrate with the trophy after the final match of the FIFA U-20 World Cup 2017 between Venezuela and England at Suwon World Cup Stadium in Suwon, South Korea
16/17 11 June 2017
Great Britain's Alistair Brownlee celebrates winning the Elite Men Columbia Threadneedle World Triathlon Leeds
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17/17 11 June 2017
Two men drink beer outside the Southwark Tavern which reopened for business today next to an entrance to Borough Market which remains closed in London
The Prime Minister insisted her Government would spend half a trillion pounds on the NHS between 2015 and 2020.
She added: "You ask about a process to ensure that people who are receiving NHS treatment are entitled to receive that NHS treatment.
"For many years there has been a concern about health tourism, about people turning up in the UK, accessing health services and not paying for them.
"We want to make sure that those who are entitled to use the services are indeed able to see those free at the point of delivery, that we deal with health tourism and those who should be paying for the use of our health service."
Ms May, appearing in the Commons ahead of the Autumn Statement, added: "We can only afford to pay for the National Health Service and social care if we have a strong economy creating wealth - and that's precisely what you're going to hear from the Chancellor of the Exchequer in a few minutes' time."
The Tory party were also attacked for failing to mention the NHS in the Government's 72-page autumn spending statement.Reuse content