A Liberal MP is calling for more guardrails as the Carney government moves to fast-track construction of major projects like pipelines, mines and ports.

Liberal MP Patrick Weiler spoke in the House of Commons on Tuesday night, breaking ranks with his party on the Building Canada Strong Act, Bill C-39.

It's an early sign that concerns are starting to bubble up within the Liberal caucus about the Carney government's changes to Canada's environmental laws.

Weiler spoke about what he sees as C-39's shortcomings, but stopped short of explicitly calling for amendments to the bill.

Critics accuse Carney government of proposing 'sacrifice zones' for the environment Among the issues the MP flagged: too much discretion for ministers to exempt projects from environmental regulations, compressed timelines which may prevent Indigenous communities and NGOs from giving meaningful input and allowing construction to begin before an environmental assessment is complete.

Weiler is the MP for West Vancouver-Sunshine Coast-Sea to Sky Country. It's a massive federal riding where environmental concerns, particular over the construction of another pipeline to the Pacific coast tend to resonate.

Weiler walking a tightrope Seemingly walking a political tightrope in the House, Weiler aired his criticisms while still managing to support the intention behind the bill.

"We need the infrastructure that will connect Canadian products to new markets and make our economy more resilient," he said. "However, there is an important question we need to ask: Can we build faster without lowering the bar?" Weiler said the answer is yes — adding he supports the overall "direction of this legislation" but called for more precautions to be built in.

He raised the issue that a future non-Liberal government could abuse the new powers the bill gives ministers and cabinet.

"Given that the powers in this bill would be permanent, it is important that where new flexibility or discretion is created, Parliament instils clear and transparent processes," Weiler said in his remarks.

The Carney government describes C-39 as one of the most important economic pieces of legislation in a generation, empowering regulators and ministers to greenlight projects within one year.

Critics warn Bill C-39 puts environment at risk September 28 Duration The legislation also includes changes to Canada's Labour Code angering unions.

The bill allows ministers to make "technical, economic and practical" considerations when permitting construction in sensitive areas.

Weiler raised the concern that new economic lens for decision-making could lead the government to abandon environmental protections because they are too costly.

He said the cost of implementing a new plan to protect caribou, for example, should not be a factor when deciding whether a species or its habitat should be safeguarded. "[Economic feasibility] should not become a substitute for achieving the environmental outcome," Weiler said.

Weiler seemed to be worried that the changes the government is proposing means communities would have less time to digest all the impacts and respond during environmental assessments — which typically offer the opportunity for those who live closest to have their say.

"Large proponents can have teams of consultants, scientists, engineers and lawyers, while smaller communities, local organizations and First Nations may not have that same capacity," Weiler said.

Carney faces climate, labour pushback over new nation-building bill He suggested the government could solve this by boosting "participant funding, access to technical expertise, clear and accessible information." "If we want a more efficient process, we also need to make sure that people have a fair opportunity to participate in it," Weiler said.

The legislation also allows shovels to hit the ground before the federal government gives a project the green light. This early construction is limited to unspecified preliminary activities that the environment minister considers are in the "public interest." For Weiler, that wording is too vague.

"Parliament should be clear on what work can and cannot be done," Weiler said. "It should not be irreversible, it should not prejudge the final decision or replace the assessment itself and it should continue to respect Indigenous consultation and environmental requirements." Weiler spoke in support of the bill's requirement for regional assessments — a study of the impact of development over a large area.

A regional assessment has been completed for wind development offshore of Nova Scotia. The 300,000-square-kilometre study area could unlock significant sustainable power generation for the province and the country.

"This gives us a chance to think about development at the scale of the ecosystem, rather than looking at small projects in isolation," he said.

Although C-39 touches on labour, nature and major projects, Transport Minister and House leader Steven MacKinnon is overseeing the bill's passage.

CBC News asked the minister's office if the Carney government was open to making changes to C-39 in line with concerns Weiler had raised, and did not immediately hear back.

Special committee for a special bill C-39 is currently before the House of Commons. The Carney government plans to use a parliamentary tool not seen since the Harper government to prioritize study once it enters the committee phase.

The government is using a "legislative committee" to study the bill's more than 200 clauses. The mechanism was used for some of the most consequential laws in Canadian history, including the Clarity Act in 2000 and the 2005 Civil Marriage Act, which legalized same-sex marriage across the country.

Carney government to study new major projects bill with tool last used in Harper era A public letter from environmental groups called for the bill to be divided up and sent to relevant parliamentary committees with expertise on the more technical aspects of the bill such as the environment, fisheries and labour.

"Its many provisions require careful, expert scrutiny that cannot be adequately addressed through a single, newly formed committee alone," said the letter signed by a dozen environmental organizations.