A care commission set up by Plaid Cymru has recommended that all social care in Wales should be free at the point of need.
It said providing services free of charge was "eminently affordable but it needs the political will to make it happen".
Plaid is now likely to turn the idea into party policy ahead of the next assembly elections in 2021.
But it accepts it does not know the "final price tag".
The commission estimated delivering the policy would cost an extra £247m a year.
It recommend the funding should come from general taxation. The sum equates to less than 1.5% of the Welsh Government's annual budget.
Last year, economist Prof Gerald Holtham said an increase of between 1% and 3% could be used to fund elderly social care in Wales.
Mark Drakeford's successful bid to be leader of Welsh Labour promised to take the Prof Holtham proposals forward.
Whereas health care is already provided free of charge via the NHS, social care is delivered by a mixture of public, private and third sector services.
"We reject the current inequity between free health care and the current payments required for many social care services, most notably people with dementia," the commission said.
"Since 80% of the current cost of social care comes from public funding, our first recommendation is that like health, all social care should be free at the point of need.
"The cost of free social care is eminently affordable but it needs the political will to make it happen."
Plaid Cymru set up the commission - made up of party members and health experts - to look for a "radical solution" to the "huge challenge" presented by social care.
An aging population and cuts to local authority budgets have placed considerable strain on social care providers in recent years.
The commission also said steps should be taken to improve the terms and conditions of social care staff and it recommends creating a single National Health and Care Service.
Plaid Cymru's health and social services spokeswoman said there is a "lot of work to do on the costings" of the whole package.
'Lot of work to do'
Speaking at the launch of the Plaid Cymru consultation on its social care proposals, Helen Mary Jones said: "That's part of the point of having the consultation now.
"We'll be able, for example, to have a better idea of what it's going to cost to bring care workers on to the same pay bands as health workers when the process that's going now of registering social care workers is done, so we know where they are, how much they're earning, and then we'll be able to work out how much it's going to cost to bring them up.
"What we haven't begun to do is to work on any of the savings that we might be able to make.
"So, for example, at the moment we know that on any given day we've got dozens of patients in acute beds costing about £600 a day who ought to be either in social care settings or in their own homes.
"If we can improve those systems and get those patients out, we're going to be making those savings. But there is a lot of work to do on the costings," she said.
Ms Jones said it was her personal belief that people in Wales "would be up for" paying more tax to fund social care changes.
The recommendations are likely to be adopted as official Plaid policy at the party's spring or autumn conference next year.