Trudeau supports finding ways to get Canada's oil resources to market, he told CBC Radio's Information Morning Fredericton.
But the Liberal leader said it would be incorrect to say he currently supports the Energy East project.
"Yes, that would be incorrect, because we are going through a process right now," he said on Monday. "That process that has been torqued and flawed by [Prime Minister Stephen] Harper is really the cause [of why] we can't get our resources to market right now."
Trudeau added: "We need to get those resources to market, whether it is Energy East, whether it is a western pipeline, whether it is Keystone XL because the alternative is more rail cars carrying oil, which nobody wants across the country."
The $12-billion Energy East pipeline project has received political support in New Brunswick from Premier Brian Gallant and Saint John Mayor Mel Norton. The federal Conservatives have also backed the pipeline proposal.
The 4,600-kilometre pipeline would carry 1.1 million barrels a day of oil sands crude from Western Canada to the Irving Oil refinery in Saint John and to the Canaport export terminal located at the entrance to Saint John's harbour.
The completion date for the proposed pipeline is 2020.
The National Energy Board has received 1,805 applications to participate in hearings on the proposed pipeline.
Trudeau said the regulatory process must be "done right." It's crucial to reassure people that their concerns about jobs and the environment are being taken seriously, he said.
The Liberal leader said he feels the regulatory process has been "politically torqued" by Harper.
"They are being cheerleaders and boosters of a particular project rather (than) referees to establish a playing field on which proponents and opponents of projects can come together and be reassured and develop those solutions," he said.
"I'm not going to prejudge the kind of process that we have to go through."
In December 2014, Premier Brian Gallant attempted to clarify some of Trudeau's comments that he made to La Presse about the pipeline project.
Gallant said he agreed that communities need to support the project, but he also felt the federal Liberal leader backed the project.
Trudeau also raised environmental concerns about the pipeline project in 2013 during a stop in New Brunswick.
Also on HuffPost