Infrastructure projects and the Energy East pipeline were on the agenda as Prime Minister Justin Trudeau and Mayor Denis Coderre met Tuesday morning in Montreal.

It was a meeting planned before a spat erupted between the provinces over the pipeline project, the two say.

Coderre has been roundly criticized since coming out in opposition to Energy East last week. He is the president of the Montreal Metropolitan Community, which represents 82 Montreal-area municipalities and cities. The group rejected the project, saying the risks of an environmental disaster outweigh any potential benefits the project may bring.

Coderre said the project is worth about $2 million a year in economic benefits to the Montreal area, while the cleanup of a major oil spill could cost between $1 billion and $10 billion.

When asked whether he would try to convince the group to change the group's opinion, Trudeau dodged the question saying the federal government’s role in the matter is to put in place a process whereby TransCanada, in this case, can demonstrate a project is in the public interest.

“What we’re going to do … is establish a clear process that will look at greenhouse gas emissions, build on work that’s already been done and give Canadians – the different levels of government, scientists, Aboriginal people – the chance to make their opinions heard and participate in the decision-making process, he said.

"You can't build a strong economy without protecting environment at same time. It's not one or the other," he said.

Trudeau went on to crticize the role the Harper government played in the process, saying they acted like "cheerleaders" instead of "responsible referees" for the process.

Coderre spoke about striking a balanced approach between economic and sustainable development.

"We said yes to Enbridge [the Line 9B pipeline reversal project] because they've done their homework, so we need to have the environmental impact [reports], we need to understand because there's no plan B for the planet," he said.

The criticisms of Coderre and the group of municipal leaders came from politicians in Saskatchewan and Alberta. Alberta Premier Rachel Notley called the Montreal-area leaders’ decision “short-sighted,” while Saskatchewan Premier Brad Wall tweeted Quebec should return the equalization payments it receives from a struggling western economy.

Interim conservative Leader Rona Ambrose criticized Trudeau's handling of it, saying, "While the PM was swanning around Switzerland with actors and billionaires, Conservatives were back at home listening to business owners and volunteers."

The meeting occurred hours before the federal environment commissioner released the results of an audit which shows the National Energy Board is failing to enforce pipeline approval conditions or follow up on compliance problems.

The prime minister must be careful, said political analyst Jean Lapierre.

“Justin Trudeau is caught. It could become a national unity crisis obviously,” he said, adding that he thinks Quebec and Coderre will eventually support the project if TransCanada addresses their concerns.

“At the end of the day, if the TransCanada pipeline does its homework, the government of Quebec will support the pipeline,” he said.

Environmental management expert Michal A. Bouchard of McGill University said he believes the mayors' concerns are justified.

“Nobody has any interest in damaging the Canadian economy and it's not done on that purpose,” he said.

Coderre and Trudeau also spoke about infrastructure projects, including light rail and prolonging the metro's blue line, as well as the effort in welcoming refugees.

-- with files from The Canadian Press