According to the ITV channel, Nick Clegg claimed that the Conservative party would have to make "deeper and deeper cuts" from other public services in order to fund the NHS.
Clegg said that his party is committed to providing the service with the extra 8 billion pounds sterling (around $12 billion) annually that NHS head Simon Stevens said it needed, ITV reported.
Clegg also called on the leaders of the Conservatives and Labour, David Cameron and Ed Miliband, respectively, to "come clean" and tell the voters whether they will provide the funds to the NHS, and how they intend to do so.
Monday marked the start of the election season in Britain, with parties formally launching their campaigns.
The UK general election is scheduled for May 7, 2015. British citizens will elect representatives to sit in the House of Commons, the country's lower house of parliament, for five-year terms.
The NHS is a crucial issue in this election.
The health agency is "working close to the limits" in most of its areas after finances decreased over the past year, the King's Fund said Thursday. The charity's assessment of NHS performance from 2010 to 2015 said waiting times were at the highest levels in years, while an unprecedented number of hospitals reported deficits.
