Canada's electoral laws are intended to limit the influence of big money in campaigns by enforcing strict contribution limits, making the names of all donors public and banning donations from corporations and unions.

But a growing number of third parties are exploiting a loophole in the law that puts no serious restrictions on how much is raised or spent before the campaign officially begins.

The newest entrants are Engage Canada and HarperPAC, and they are not really third parties so much as offshoots of the three main political parties.

Engage Canada was started by two former senior Liberal staffers in Ontario, Don Guy and Dave Gene, and Kathleen Monk, an equally prominent federal NDP strategist. Take my word for it, because you won't find any disclosure of who is behind the group from its website.

On the other side is HarperPAC. The name tells you all you need to know.

The group is a "political action committee" in the U.S. mould and dedicated to re-electing the Harper government.

It's the brainchild of Stephen Taylor, the former Manning Centre and National Citizen Coalition activist, and a dozen former Conservative staffers whose photos and bios are prominently displayed on the group's website.

PACs aren't entirely new to Canada. In Ontario, a coalition of unions under the banner Working Families is credited, or blamed, for undermining the campaign of former provincial Conservative leader Tim Hudak in the 2014 election.

Engage Canada is a kind of offspring of Working Families. Unions, prohibited from financing candidates or political parties during a federal campaign, are important contributors.

Though how much they're donating, Engage Canada isn't saying.

Proxy attacks

That, of course, is their right, since nothing in the Elections Canada Act requires them to abide by the rules until the campaign officially begins.

One union that is openly acknowledging involvement — though not how much it's giving to Engage Canada — is the 315,000-member Unifor, which represents, among other groups, journalists at 35 media outlets (but not the CBC).

Let the campaigning begin. A woman takes a selfie with Conservative Leader Stephen Harper as he hands out chicken meals as part of Quebec's Fete Nationale celebrations on Wednesday. (THE CANADIAN PRESS)

Unifor national president, Jerry Dias, says the goal is to peel away the veneer of the Harper Conservatives as good economic managers and protectors of services like health care.

"I can't instruct our members how to vote, so we're going to lay out the facts and they're going to determine who they're going to vote for,'' he says. "It's clear to us the Conservatives' policies have been disastrous for our country."

Not surprisingly, over at HarperPAC the goal is to attack the Liberals and NDP.

The group has already put out ads branding Liberal Leader Justin Trudeau as immature: one offers a man's voice sombrely tells us Trudeau is blaming Canadians for his party's poor showing in recent public opinion polls.

Stephen Taylor insists his group's role is not just to run attack ads against the Liberals and NDP.

"We look at areas where there will be an intense political discussion ramping up towards the fall,'' he says. "And we think that those parts of the country are going to be more receptive to having a discussion about issues that are important to Canadians."

But whose money?

The real issue with these PACs, however, is not just the messaging, but the refusal to disclose how much money is being raised and from whom.

It's clear the two sides are ramping up the attack ads before the campaign formally begins to avoid the demands of transparency and accountability required under election law once the writ is dropped.

While Liberal Leader Justin Trudeau poses with young participants at the annual St-Jean-Baptiste Day parade in Montreal. (THE CANADIAN PRESS)

And that's a problem, says Sheila Krumholz of the Centre for Responsive Politics, a Washington-based non-profit group dedicated to tracking who's spending what in U.S. politics on its website, www.opensecrets.org.

A quick glance will show you the money being raised and spent in the U.S. is in the hundreds of millions of dollars.

"That's really the worst of all worlds to have both unlimited fundraising and spending with no record, no information for voters on where the money is coming from, who's bankrolling these efforts," she says.

Krumholz also feels there is another concern with these PACs, both in the U.S. and Canada, which is the role given them by the main parties — if only informally — to attack and misrepresent their opponents' positions on certain issues.

"Studies have shown that outside interest groups run ads that are far more negative, far more deceptive, and that's a concern because in some cases, the public doesn't have any information about who's behind the group, who's running it."

Free speech

Many political observers in the U.S. blame PACs for suppressing voter turnout by turning off voters so completely that they simply stay at home.

Still the U.S. Congress has shown little interest in curtailing these groups, and the same may be true here, where the uber-partisanship of American politics has worked its way into Parliament and Canadian campaigns.

NDP Leader Tom Mulcair enjoys a beer while touring a microbrewery in Quebec City Tuesday. (Jacques Boissinot/Canadian Press)

Back in private life, when he was head of the National Citizens Coalition, Stephen Harper challenged restrictions on third-party advertising during campaigns all the way to the Supreme Court of Canada, arguing it was a violation of freedom of speech.

The court ruled against him.

Given his position then, it's hard to see the Harper government moving to limit the activities of third parties outside of the campaign period. Or his political opponents from taking the very same position.

So get used to it. The months heading into election 2015 are sure to be filled with attack ads on all sides, bought with millions of dollars donated by anonymous sources with not-so hidden agendas.