It's a massive infrastructure project that everyone agrees must be done, but nobody wants to own.

As work proceeded over the weekend to repair the costly, crumbling Champlain Bridge in Montreal – a vital commercial and commuter link – the politically radioactive issue of tolls to pay the replacement bill is expected to figure prominently in Quebec leading into the next federal election in 2015.

Prime Minister Stephen Harper has floated the idea of transfering ownership of the St. Lawrence span to provincial authorities if they want to avoid unpopular tolls.

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There are massive dollars involved. Replacing Champlain Bridge, which decayed prematurely, stands to cost Canadians up to $5-billion. The Conservatives are insisting tolls are necessary to ensure Canadian taxpayers don't foot the entire bill for the "local" bridge, scheduled to be built by 2018.

The plan has been panned by almost all other politicians in Quebec, where the thought of putting tolls on the biggest bridge in Montreal – but not on the dozen of other entry points – is seen as poor transit planning.

The strategy is also putting pressure on the federal NDP and the Liberal parties, which oppose the Conservative plan, to come up with distinct proposals to pay for the new bridge. Voters in the Montreal area are likely to be swayed by the pocket-book issue of tolls, and there are fears that commuters will clog other bridges in the area if Champlain is the only one with tolls.

The federal authority that runs Champlain, Jacques Cartier and Champlain Bridges Inc. had to conduct an emergency installation of a so-called "super beam" last fall, to prevent a cracked concrete support from failing completely. This weekend, crews worked on a new truss in a $1.5-million job to remove the super beam, and save it for the next crisis. Lanes of the bridge were closed all weekend, but it remained partly open.

Progress was slowed by high winds, and work is expected to continue next weekend.

La Presse released a letter last week in which Mr. Harper told the Quebec government he was open to "confidential" discussions to turn over strategic infrastructure over the St. Lawrence Seaway. Ottawa is not only looking to unload Champlain Bridge, but also the nearby Jacques-Cartier Bridge and the portion of the Honoré-Mercier Bridge it controls.

But last month in the House, Mr. Harper said he would not budge on tolls.

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"The government is building a new major local bridge in the city of Montreal. We are not doing this in any other part of the country. The only basis on which we can do that is with financial participation by the local people. That means if there is not a toll, there will not be a bridge," Mr. Harper said.

The cash-strapped Quebec government opposes Ottawa's plans to impose tolls on Champlain Bridge, and it is refusing to engage in long-term talks over the ownership. "This is not a priority," Quebec Premier Philippe Couillard said last week. "The issue on the table at this point is focusing on meeting deadlines to repair and upgrade the bridge."

Montreal Mayor Denis Coderre argues that tolls don't make sense on a replacement bridge, but he has all but given up on changing Mr. Harper's mind. "There will be a [federal] election in the meantime," Mr. Coderre told reporters earlier this month.

Mr. Coderre has noted 82 municipalities, the truckers' associations and several Quebec boards of trade have joined the Quebec government in opposing tolls.

The NDP has slammed Ottawa's stance, with Leader Thomas Mulcair comparing Mr. Harper with a "used-car salesman" for planning to download the Champlain Bridge.

The NDP is refusing to endorse Ottawa's proposal for tolls, stating that a comprehensive regional plan is needed before a decision is made. The federal Liberals are also stating that there needs to be a full plan for the new bridge before deciding on tolls.