Margaret Hodge, who chairs PAC, said: "Promoters of 'boutique' tax avoidance schemes like the one brought to our attention by the case of Jimmy Carr, are running rings around HMRC.
She added that schemes which exploit loopholes within the system are being taken advantage of.
"It has allowed a system to evolve where the dice are loaded in favour of the promoters of tax avoidance schemes," she said.
More top news
A new Halloween-themed Harry Potter story by J.K. Rowling will be published online today.
The chair of an inquiry into an alleged historical Westminster paedophile ring has been accused of 'editing' details of her impartiality.
There has been a sharp and worrying rise in the number of youngsters contacting ChildLine about suicide, the children's charity has warned.