Labour has been "slashing" the NHS budget in Wales, the Welsh Conservatives have said, leading to "devastatingly long waiting lists".
Assembly Tory leader Andrew RT Davies said although devolved, health was one of the main election issues for voters.
"Wherever you go across Wales people raise the issue of the NHS, and Labour are running the NHS in Wales," he said.
Labour responded saying that Tory sums on the NHS "simply don't add up".
Mr Davies said Welsh Conservatives would protect health spending and introduce a cancer drugs fund.
He defended his party's decision to campaign on an area of policy that was not controlled in Wales by Westminster.
"(Labour leader) Ed Miliband has used the example of 'compare and contrast', and I think it is perfectly reasonable to point out we don't have a cancer drugs fund here in Wales and some of the most disappointing ambulance response times on record," he said.
"There is a real dilemma for voters in May. Do they want to vote for the Conservative party who want to protect health spending or do they endorse a party who have drastically cut health provision in Wales?"
But Welsh Labour's Deputy Health Minister Vaughan Gething accused the Conservatives of wanting to privatise the NHS.
"The Tories have had three opportunities in the campaign so far to rule out privatising the NHS and they have refused to do so" he said.
He added: "This election is a clear choice between a Labour government that would invest in the NHS to train an extra 1000 doctors, nurses and front-line staff, or a Tory government that would introduce a tablet tax for sick people and privatise health services."
Elsewhere on the campaign trail on Monday, Welsh Lib Dem leader Kirsty Williams was promising better rural health care while visiting target seats in mid Wales.
Ms Williams said her party wanted to invest in cottage hospitals and community care.
"An urgent care centre in Montgomeryshire is essential if we are to relieve pressure on A&E departments and cut waiting times," she said.
Plaid Cymru accused its rivals of neglecting the economy of north Wales.
Party leader Leanne Wood said: "Every community has a stake in making our country a success and it is time the north of Wales got the investment and vision it deserves from governments in Cardiff and London."
UKIP's leader in Wales Nathan Gill was campaigning in Brecon and Radnorshire.
Meanwhile Labour has promised more powers for Wales over transport, energy and assembly elections in its manifesto launched in Manchester on Monday.