Pop superstar singer Madonna's Kabbalah religious group is under the scanner of US revenue officials.

According to Newsweek.com, the trendy religious group is reportedly under scrutiny by the US Internal Revenue Service (IRS) for its tax-exempt status.

According to a source, the IRS seems to be paying special interest to the organisation's Spirituality for Kids foundation.

A source says, "Madonna has raised millions for Spirituality for Kids. The question is whether some of that not-for-profit money has been ploughed into for-profit enterprises."

Madonna recently embraced the relatively unknown religion which is an offshoot of the more mainstream Judaism.