A federal advisory group has urged the Canada Revenue Agency to either close the loophole or accept that charities can now freely engage in partisan politics - such as campaigning to defeat sitting MPs who support same-sex marriage.

"It's an issue - it is something that does need to be resolved," Lois Hollstedt, chair of the charities advisory committee, said in an interview.

The problem was identified last year when the committee wrote to John McCallum, then Liberal minister of National Revenue, warning that some charities appeared to be flouting the rules.

"In recent months, we have seen an increasing amount of political-like activity by some charities," Hollstedt said in a letter obtained by The Canadian Press under the Access to Information Act.

"In the committee's view, much of this activity appears to cross the line from what is considered permissible political activity . . . to the type of activity the sector has always understood to be prohibited."

The letter warns that some charities have defended their partisan campaigns against sitting MPs by arguing that the wording of the law prohibits such activity only during election campaigns, and not at other times.

"If the current prohibition on 'partisan political activities' does not apply to elected members, but only to candidates, the committee is of the view that amendments to the Income Tax Act be considered to rectify this anomaly."

In a written response, the agency said it "recognizes this is an issue and that the current guidelines require more extensive revision."

Charities that break the agency's rules on partisan politicking can have their tax-exempt status revoked, though Ottawa has never done so.

"There are some who believe that certain types of charities are being given a 'free pass' to do whatever they wish because of perceived consequences that would result from these substantial organizations having their status revoked," the advisory group warns in its letter.

The problem is bound to heat up this fall as the House of Commons prepares for a vote on whether to revisit legislation that allows same-sex marriages. The vote was a Tory election promise.

Last week, a Christian group opposing same-sex marriage said it would work to topple Tory MP Garth Turner by having another candidate secure the party nomination in the Ontario riding of Halton for the next election. Turner is a supporter of same-sex marriage.

In 2004, the Canada Revenue Agency made headlines when it threatened to revoke the charitable status of the Roman Catholic Church in Calgary because of allegedly partisan comments by Bishop Fred Henry during the federal election in June that year.

The bishop had posted a letter on the diocesan website criticizing then Prime Minister Paul Martin, but the agency never followed through on its threat.

A 2002 agency policy statement says that a "political activity is considered partisan if it involves direct or indirect support of, or opposition to, a political party or candidate for public office. . . .

"A charity must not single out the voting pattern on an issue of any one elected representative or political party."

The agency also issued an advisory last December, during the election campaign, reminding charities about prohibitions on partisan politics under Section 149.1 of the Income Tax Act.

Asked for comment on the issue, a spokeswoman for the Canada Revenue Agency said only that "what constitutes partisan political activity has not changed in any way over the years."

Jacqueline Couture added there is no pending change to the Income Tax Act, but that "we review the (policy) documentation regularly."

Hollstedt said her 12-person committee, whose scheduled meeting in June was suspended as the new Tory government reviews its need for such bodies, was unanimous in condemning the trend of charities entering the political fray.

"This was an issue that we all had one perspective on, which was that partisan political activities are not acceptable under any conditions," she said from Vancouver. Instead, what had seemed a clear prohibition has become "fuzzy".

"Charities need to be given a clear message," said Hollstedt, who ran Vancouver's YWCA for 15 years and is currently chair of the board of Community Living British Columbia.