Groups including Greenpeace Canada, the Council of Canadians and the David Suzuki Foundation say in a letter to the federal regulator that the application shouldn't be considered until the review process is overhauled.
The groups say they believe there hasn't been enough consultation with the public, shutting out those worried about climate change and ignoring First Nations concerns.
The National Energy Board could not immediately be reached for comment.
If approved, the Energy East project would ship 1.1 million barrels of crude a day from the Alberta oilsands to refineries in Quebec and New Brunswick through 4,600 kilometres of pipeline.
In April, TransCanada (TSX:TRP) said the completion of Energy East would be delayed by two years to 2020.
That came as the company announced it was searching for a new location for a planned marine terminal in Cacouna, Que., that was scrapped last fall because of concerns about nearby beluga whales in the St. Lawrence Seaway.
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