The British public back Ed Miliband's plan to tax houses worth more than £2m, according to a poll from YouGov for The Times.
The survey found that 30% of respondents "tended to support" the "mansion tax" proposal and 42% of people "strongly supported" the policy.
But only 7% of respondents said they "strongly opposed" the idea and 11% said they "tended to oppose" the plan.
Miliband, speaking at the Labour Party annual conference in Manchester, said the move would help fund a massive recruitment drive for the NHS if Labour is elected after the 2015 General Election.
The proceeds would go into a £2.5bn ($4.1bn, €3.1bn) "time to care" fund to create 20,000 more nurses, 8,000 more GPs, 5,000 more care-workers and 3,000 more midwives by 2020.
"That is what the next Labour government will do and we will do it together," Miliband said.
But the details of the levy, which was first proposed by the Liberal Democrats in 2009, have yet to be revealed.
The poll findings come after Labour Party leader was attacked over the pledge
"Labour's proposal to tax expensive houses and hypothecate the funds for the NHS is bizarre," said Ben Southwood, the head of policy at free market thinktank the Adam Smith Institute.
"Although property value taxes are among the least inefficient taxes, and shifting the burden from costlier taxes like stamp duty land tax, corporation tax and income tax is a good idea, we already have a perfectly good property tax system: council tax.
"The only problem with the council tax system is that, for political reasons, it has not been revalued since 1993, massively distorting the system.
"It makes no sense to create a whole new property tax system at an arbitrary £2m cut-off point: instead, council tax should be revalued and remodelled along more progressive lines, to reduce the tax burden on people in less expensive properties."
The Labour Party also sped ahead of the Conservative Party in the opinion polls.
A YouGov survey for The Sun revealed that 37% of people would vote for Miliband's party at the 2015 General Election, against 31% who would vote for the Tories.