The Liberal Democrats want local authorities to have the power to charge 200 per cent council tax on second homes.
Party leader Nick Clegg made the announcement in Cornwall, the county with the largest proportion of second homes in the UK - around five per cent of the 260,000 houses and apartments are regarded as second properties.
Cornwall Council was the first in England to levy a 150 per cent council tax rate, on homes left empty for two years or more.
On a campaign visit to Cornwall, Clegg claimed the higher tax could help "particularly in such a wonderful part of the country as this where there are so many people with second homes and where the prices, because of that, are way beyond the reach of many young people wanting to get their feet on the first rung of the property ladder".
However, a Lib Dem party spokesman then told the BBC: "We are not saying this will be imposed".
At the time of the 2011 Census, some 1,570,228 residents in England and Wales (about 2.8 per cent of the official population) reported having a second address in another local authority in England and Wales, that they used for 30 days or more each year.
Another 47,733 residents of England and Wales (around 0.1 per cent of the official population) had a second address in either Scotland or Northern Ireland.
And on top of that, another 820,814 (1.5 per cent of the English and Welsh population) had a second address overseas.
Some 77 per cent of these ‘second’ properties were recorded in the Census as being for purposes other than holidays - so for example, an address of student accommodation.
Some 12 per cent were recorded as being for work and only 11 per cent (165,095 in total) were recorded as being for holiday purposes.
At the time of the Census, Cornwall was the local authority where the greatest number of people recorded a second address. Some 22,997 people, usually resident elsewhere in England and Wales had a second address in Cornwall, used for 30 days or more each year - the official designation.