MP Margaret Hodge, Chair of the Committee of Public Accounts, said that HM Revenue and Customs (HMRC) is losing out to the sum of around £5 billion every year because of tax avoidance schemes.
And she believes a lack of transparency about who is behind these schemes is not helping the department's cause.
Ms Hodge added that promoters of "boutique tax avoidance schemes" should be brought to the public's attention.
"They create schemes which exploit loopholes in legislation or abuse available tax reliefs such as those intended to encourage investment in British films, and then sign up as many clients as possible, knowing that it will take time for HMRC to change the law and shut the scheme down," she explained.
"Their clients can then take advantage of this window of opportunity to make a lot of money at the expense of the UK taxpayer, while the promoter simply moves on to a new a scheme and repeats the process."
It comes after the government announced last week that it would be stopping procurement contracts from going to tax avoiders.
Posted by Thomas Fletcher