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
Showers could be heavy for a time but most should still enjoy sunny spells.
The chief executive of EDF has urged the government to go ahead with the new nuclear plant.
An Italian prosecutor investigating the quake aftermath believes cheap renovations may be partly to blame for the high death toll.