The executive director of Biathlon Canada said Monday tax lawyers had assured her that the group's tax-shelter arrangements were legitimate.

The Canada Revenue Agency has revoked the charitable status of the group, which has its headquarters in Ottawa.

"[It's] very harsh and very disappointing for our organization," said Joanne Thomson.

"The money that we received, we were able to use it, and the rest is re-invested so we can receive returns annually. It's hoped to have revenue more than you started with, and it's something valuable for our organization," she said.

Biathlon Canada is the governing body for the shoot-and-ski sport, and it provides financial support for the national team.

The CRA says the organization issued more than $25 million in donation receipts for "abusive transactions using a tax shelter".

Biathlon Canada won't reveal the specific cases, but the general practice involves taking a donor's charitable gift, and matching it with money from a third party lender. That greater sum is then invested for the charity. The donor gets a tax receipt for the entire dividend, not just the original donation.

Ottawa tax lawyer Adam Aptowitzer said Biathalon Canada is just the latest charity using these arrangements to have its charitable status revoked.

But in many ways, the donors are the real victims.

"The CRA comes along several years later and goes after the taxpayer, and voids that donation except for that dollar they are out of pocket, and asks for penalties and interest going back several years.

"And it's really brought many families to financial destruction, because they were taken advantage of by these tax shelters," Aptowitzer said.

As of late 2008, CRA had denied $2.5 billion worth of claims for charitable tax credits.

It's warning consumers to stay away from these heavily marketed schemes.

Three years ago, the Canada Revenue Agency warned Biathlon Canada the tax-shelter system it was using violated income tax laws.

Biathlon Canada stopped using the system. But CRA stripped the group of its status anyway because it had issued millions in questionable tax receipts.

Aptowitzer said CRA is auditing these arrangements because taxpayers end up subsidizing the organization.

"You're a dollar out of pocket, but you have a receipt for more than that, which effectively entitles you to more from everyone else's pocket. So you can see why CRA has taken a hard line on it, and why it's very offensive to many people," Aptowitzer said.