The extra money includes £1billion earmarked specifically to reduce backlogs and to deliver routine surgery.
The Government said the funding would take total Covid-19 support for the NHS to more than £34billion this year alone.
Health bosses had warned last week that the NHS will need approximately £10billion more a year in order to adapt to living with coronavirus.
The announcement of extra cash for the NHS comes as Mr Johnson faces a Tory rebellion over his plan to increase National Insurance contributions to raise an additional £10billion a year in tax revenue to pay for a social care overhaul.
Boris Johnson today announced a £5.4billion cash injection for the NHS for the next six months to help the health service clear the treatment backlog caused by the coronavirus crisis
Health Secretary Sajid Javid admitted treatment waiting lists ‘will get worse before they get better’ but said the extra money will help the NHS deal with the backlog
Some £2.8billion of the additional money for the NHS will be allocated to cover costs relating to enhanced infection control measures to prevent the spread of Covid-19.
Just shy of £500million will be spent on boosting the hospital discharge programme to free up more beds.
Mr Johnson said: ‘The NHS was there for us during the pandemic – but treating Covid patients has created huge backlogs.
‘This funding will go straight to the frontline, to provide more patients with the treatments they need but aren’t getting quickly enough.
‘We will continue to make sure our NHS has what it needs to bust the Covid backlogs and help the health service build back better from the worst pandemic in a century.’
Health Secretary Sajid Javid admitted treatment waiting lists ‘will get worse before they get better’ but said the extra money will help the NHS deal with the backlog.
‘Today’s additional £5.4 billion funding over the next 6 months is critical to ensuring the health service has what it needs to manage the ongoing pandemic and helping to tackle waiting lists,’ he said.
‘We know waiting lists will get worse before they get better as people come forward for help, and I want to reassure you the NHS is open, and we are doing what we can to support the NHS to deliver routine operations and treatment to patients across the country.’
The funding announcement came as Mr Johnson and Chancellor Rishi Sunak continued to haggle over the detail of a social care overhaul.
The PM is preparing to defy a huge Tory revolt to push through a £10billion tax raid.
Mr Johnson looks determined to push ahead with hiking National Insurance contributions by at least one per cent, in spite of a rising clamour that it would flout a manifesto pledge and hit working age people hardest.
The PM has been locked in talks with Chancellor Rishi Sunak (pictured) and signed off an immediate £5.4billion funding boost for the NHS to help it through the winter
Amid a wave of criticism before the policy has even been formally unveiled, former party leaders and three ex-chancellors have joined ‘Red Wall’ MPs urging a rethink.
Cabinet minister Jacob Rees-Mogg has issued a thinly-veiled warning by pointing to George Bush’s famous broken promise: ‘Read my lips, no new taxes.’
Meanwhile, Sir Keir Starmer has signalled that Labour will oppose the long-awaited blueprint for tackling the social care crisis – raising the possibility that the Government will struggle to get the measures through Parliament.
Mr Johnson has been wrangling through the weekend with Mr Sunak to finalise the details of the proposals, after the Chancellor demanded more revenue to foot the costs of the new system. Downing Street is hoping to announce the results tomorrow.
But there is disquiet about how parts of the package have been allowed to leak. ‘We seem to be spending a lot more time talking about how we are paying for it than what we are doing,’ one senior source told MailOnline.
The 2019 Tory manifesto committed to a ‘triple lock’ on taxes, with no rise in income tax, VAT or national insurance.
No10 has been talking up rumours of an imminent reshuffle in a bid to quell unrest among ministers, and the platform is expected to be rubber-stamped tomorrow at the first Cabinet meeting since the summer break.
‘I’ve seen it reported that five Cabinet ministers are opposed to the idea,’ an insider told the Mail. ‘The truth is you would struggle to find five of us who are in favour. We made a promise not to raise taxes and we have to honour it.
‘If we go down this road it will come back and bite us, whatever No10’s polling might tell them. People are very unforgiving when it comes to tax.’
A Treasury source said: ‘The PM is in invincible mode in meetings. Rishi’s team has proposed a series of cheaper alternatives but none works for the PM.’
Another said: ‘They’re still haggling over the cap.’
Mr Johnson will have been reassured by a YouGov poll showing strong public support for raising national insurance. There is speculation that a 1.25 per cent rise will be used to set a lifetime cap on care costs of around £80,000.