Jonathan Isaby from the TaxPayers' Alliance said taxpayers would "resent" paying for spare rooms for those receiving housing benefits "when they can't have one themselves."
He said: "I'm not saying that there aren't people who do need those rooms but you can't have a blanket exemption for hundreds and thousands of people."
Campaigners against the Government's so-called 'bedroom tax' will take to the streets tomorrow in protest of the proposals.
More top news
A head chef lost more than half his 36st body weight thanks to tough love from a friend who called him a fat f***" every day for six weeks.
It comes after the government announced international GCSEs, which many private schools use, would be dropped from the league tables.
Rape suspects will need to prove to police that a woman consented to sex under fresh new guidance in sex offence cases.