The Liberal Democrats are considering whether to extend their 'mansion tax' policy to cover other properties, including second homes.
The BBC reports an internal consultation paper being drawn up says there "may be merit" in applying the proposed 1% levy on people with a property portfolio worth more than £2m. The policy was originally going to apply only to one property, but could now be extended to cover other homes.
Other reports said plans to tax assets such as jewellery are also being looked at.
Labour backed the £2m mansion tax on Thursday.
The Lib Dem policy, set to be debated at the party's spring conference next month, could see owners of rented properties and holiday homes on the hook for the tax.
The Mail on Sunday and Sunday Times report other options under consideration include a French-style wealth tax on personal assets, such as jewellery and paintings.
However, business secretary Vince Cable played down the reports. He told Sky News the ideas were a bit "wacky" and "emphatically not party policy".
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