With a federal election just four months away in Canada, a political war has emerged between dueling lobby groups as to who can spend the most money to blanket the airwaves with hyper-partisan election advertising.

Engage Canada, committed to ousting current Prime Minister Stephen Harper, and HarperPAC, which is working to keep him there, are vying to outspend each other as the final stretch of the pre-campaign kicks into high gear.

Both groups opened up shop in recent weeks, amid an uncertain political landscape that has pitted all three parties at a virtual tie.

Canada's campaign finance laws are generally pretty strict. During a campaign, political parties have hard caps on how much they can spend, roughly $20 million per party. Individuals can contribute no more than $1,500 to each party per year. Corporations and unions cannot donate to parties or candidates, and third-party groups are practically banned from partisan advertising during a campaign.

But there's one big loophole that makes SuperPACs possible — there are virtually no rules on spending in the lead-up to the formal campaign period, which usually lasts just 36 days. Third-party groups can raise as much money as they want, from whoever they want, and spend it however they want.

This marks the first time this model of unbridled spending will feature so prominently in a federal campaign in Canada. Two significant differences: there is an outgoing majority government, and a fixed election date.

So, as both sides of the political spectrum begin dumping cash into negative advertising, each side is accusing the other of being backed by corporate and union interests, raising worries that Canada is quickly moving towards the American model of polarizing, big-money political turf wars.

The first big entry on the national stage was Engage Canada, a team of left-leaning strategists and ex-staffers for the New Democratic (NDP) and Liberal parties. They ran their first ad earlier in June, accusing the Harper government of exacerbating income inequality by aiding the rich, and cutting programs that aid the poor.

Engage Canada's first ad

VICE News reached out to the organization to talk about their strategy.

Jessica Hume, an ex-journalist who was hired on as a spokesperson for the group, said the idea is to identify targets across the country, and blast them with ads challenging the record of the Harper government.

Hume said the founding of Engage Canada was in direct retaliation for two other SuperPACs that have sprung up in the last year — Working Canadians, and Conservative Voice. The former managed to run a handful of radio ads, while the latter appears to be defunct.

"I think what we're trying to say here is that they've had too much of a monopolization on that conversation," says Hume.

Just like their conservative counterparts, Engage Canada does not publish a list of its organizers or advisors on their website. Journalists have been able to cobble together a list of former chiefs of staff and communications advisors to various center-left governments and parties across the country that are involved in the project.

When VICE News asked for more details about the group's fundraising efforts — how much they've raised, who's contributed, the proportion coming from unions or companies — Hume wouldn't say.

"We're not going to talk about money," she said.

The irony of the advertising is that both the NDP and Liberals have long railed against money in politics, regularly accusing conservative groups from benefiting from corporate cash. VICE News asked whether there was some hypocrisy in those parties now benefitting from unrestricted money.

"I take your point," says Hume. "At the same time, we're all playing by the same rules."

The first real foray into SuperPACs was done during the 2011 Ontario provincial election, when the Working Families Coalition ran a series of damaging ads against Progressive Conservative Party leader Tim Hudak. Engage appears set to model its approach on that one.

On the conservative side, HarperPAC appears poised to become the most organized, high-profile pro-government advertising effort. Their leadership — which, unlike Engage Canada, is posted on the website — includes various former advisors for the Harper government, as well as a former justice minister of the province of Alberta.

"The plan is to match the effort of the left wing organizations that have risen to take on, and in their words 'unelect' Stephen Harper," Stephen Taylor, a spokesperson for the group, told VICE News.

Taylor says he, as the former director of the right-wing National Citizens Coalition (a job which Harper held previously) has always supported allowing groups to engage in American-style advertising. Even the left-wing ones.

"We actually don't challenge their right to do, we are just reacting to the fact that they're doing it," Taylor says.

Even so, HarperPAC described itself in a press release this week as "a group that aims to defend the interests of everyday Canadians against the tide of cash from professional leftist agitators and big union bosses that has been earmarked to take down the Conservative government."

VICE News tried to get information about who has contributed to the group thus far, to no avail.

"We're keeping those cards close to our chest thus far," Taylor says. He says that while they've not yet raised millions — like Engage has claimed it has — "we are in the process."

He says the group will spend every dime it receives this summer, meaning the only limit on political advertising in the next few months will be how deep their supporters' pockets are.

The federal election is on October 19, 2015.

Follow Justin Ling on Twitter: @justin_ling

Watch the VICE News Documentary, '**Election Day in Turkey: Ballots, Watchdogs, and Fraud.'**