May came under fire following a speech in Wales, where her Conservatives are hoping to make historic gains.
May came under fire following a speech in Wales, where her Conservatives are hoping to make historic gains against the opposition Labour party in the June 8 general election.
In the speech she announced a cap on the amount people would be asked to pay, which was in response to a backlash against proposals in her party's manifesto on paying for elderly care.
"We are proposing the right funding model for social care... We will make sure there's an absolute limit on what people need to pay," she told supporters in Gresford, a village in north Wales.
May denied the cap amounted to a U-turn, repeating three times that "nothing has changed" when questioned by journalists on the announcement.
The initial proposal did not include an upper limit, leaving it open to accusations that people could be forced to use their assets to pay for care.
She did not detail how much the limit on elderly care would be.
Labour said the prime minister's change of heart had thrown her campaign into "chaos and confusion", just four days after the Conservative Party manifesto was published.
"This is weak and unstable leadership. You can't trust the Tories -- if this is how they handle their own manifesto, how will they cope with the Brexit negotiations?" said Andrew Gwynne, Labour's election co-ordinator.
Negotiations on Britain's departure from the European Union are expected to start later in June after the general election.
The former leader of the UK Independence Party, Nigel Farage, said May's change was the second such turnaround following an earlier shift on the government's budget plans.
"U-turn on the budget and now a U-turn on the manifesto. This lady is for turning," he wrote on Twitter, in reference to a famous phrase used by former prime minister Margaret Thatcher.
Pressure has mounted on the Conservatives following their manifesto being published on Thursday, with weekend polls showing their considerable lead over Labour narrowing.
The landslide predicted by the earlier 20-point lead has shifted to put the Conservatives on 44 percent and Labour up to 35 percent, according to a YouGov poll for the Sunday Times newspaper.
The ruling party's manifesto also promised MPs a vote on scrapping a ban on fox hunting, a pursuit unpopular with the electorate but which has the backing of a minority of dedicated Conservative supporters.
An anti-fox hunting protester was arrested on Monday morning, outside the venue where May was to speak.