George Osborne is facing unease on the Tory benches over the prospect of cuts to the top rate of tax, with one MP warning the the public would not understand why the rich needed a tax cut.
The chancellor is widely expected to use his Budget statement tomorrow to set out how he intends to reduce the 50p rate for people earning more than £150,000 a year.
The move has been warmly welcomed by some Conservative MPs who believe the 50p rate - introduced by the last Labour government - is a deterrent to enterprise and is holding back growth.
They argue that it is an inefficient means of generating revenue, with the wealthy able to avoid paying or simply leaving the country - a view expected to be supported by research by HM Revenue and Customs due to be published alongside the Budget.
But others in the party fear that it will play into the hands of Labour, enabling them to argue that the Tories are handing a tax cut to the better-off at a time when low and middle-income earners are still feeling the economic squeeze.
Conservative backbencher Jesse Norman told BBC Radio 4's The World At One: "I do think that the possibility of cutting the top rate is a concern. I don't think people will understand that this is being done in order to raise more money.
"That idea I don't think is going to get across without an enormous amount of communication."
Labour continued to press home their attack, with shadow Treasury minister Owen Smith describing a cut in the 50p rate as the "wrong priority".
"At a time when there is a huge squeeze on families on middle and low incomes, cutting the top rate of tax for people on over £150,000 would be completely the wrong priority and show just how out of touch this Government is," he said.