David Cameron has pledged to protect the NHS by meeting its funding needs "in full" and Labour is to announce plans to provide an extra 3,000 midwives to guarantee one-to-one maternity care.
While the countdown to the too close-to-call general election continues, the main parties are trying to win over crucial undecided voters for whom the NHS is a key issue.
:: Full Coverage Of General Election 2015
The Prime Minister has promised to fund the five-year reform plan put forward by NHS chief executive Simon Stevens by pumping at least an extra £8bn a year into the health service by 2020.
This will mean that over-75s will be guaranteed same-day access to GPs, patients will be able to see doctors out of regular office hours and the NHS will provide a full range of services seven days a week, according to Mr Cameron.
Mr Stevens predicted in a report in October that, if health spending rose only at the rate of inflation, growing demand for care would leave the NHS in England with a £30bn funding gap by 2020.
He said around £22bn of that could be met through "efficiencies", but the remainder would have to come from government funds.
Up to now only the Liberal Democrats had committed to finding the extra money.
Mr Cameron said his track record showed he could be trusted to protect the NHS, with annual spending up £7.3bn in real terms but he did not say where the extra funding needed would come from.
Speaking about his severely disabled son Ivan, who died in 2009, Mr Cameron added: "As someone who's been supported by the NHS at the most difficult time in my life, I'm utterly committed to ensuring it is there for everyone when they need it too.
"That's why I'm backing the NHS's own plan with the cash required to ensure it can continue to deliver an amazing service to patients and their families in the future."
Health Secretary Jeremy Hunt said a strong economy was needed to support a strong NHS.
He added: "We need to do much more to ensure our vulnerable elderly can be treated in the community.
"That is why we are building on our decision to bring back named GPs for the over 75s, by ensuring that as a part of this they are guaranteed a same day GP service when they need it.
"This means family doctors can focus on giving elderly people the care they need and prevent unnecessary trips to hospital."
But a Labour Party spokesman said: "The Tories are briefing the same story they've done five times before. There is still no firm commitment, still no idea where the money coming from - and they still can't be trusted on NHS."
And a Lib Dem spokesman said: "The Conservative ideological obsession with cutting the size of the state means they cannot afford this unfunded spending commitment.
"The Liberal Democrats are the only party who has committed to giving the NHS the £8bn it needs and have set out how we will pay for it.
"Tory spending plans will not help the NHS but rather destroy vital public service and decimate basic entitlements."
Labour will publish a mini-manifesto later including a new right to a dedicated midwife before and after childbirth.
Joining Mr Cameron in seeking to highlight his own personal experience of the NHS, Labour leader Ed Miliband told of the "brilliant care" he and wife Justine received when their sons Samuel and Daniel were born.
Evoking the popular 1950s-set TV programme, he said: "Call The Midwife shouldn't just be a TV programme from the past but part of our NHS future too.
"We need to ensure the NHS can offer every woman the personalised one-to-one care we expect from a modern and thriving health service.
"Our fully-funded plan will provide the extra staff including midwives needed to give them the time to care. Because it is time to care for our NHS."
:: Click here to make your own Government with our Shaker Maker
