About a dozen people staged a rally Monday in Halifax as the board met with groups during closed-door meetings to discuss the project.
Members of Stop Energy East Halifax held signs and a makeshift pipeline with the words "tar sands=climate bomb" in front of the Halifax Central Library.
Over the next week, National Energy Board officials will meet with groups in the four Atlantic provinces to discuss how it can improve its pipeline safety and environmental protection programs, part of a cross-country tour.
Board chairman Peter Watson was in Halifax on Monday to meet with groups including the Maritimes Energy Association, petroleum engineering students at Dalhousie University, Antigonish's deputy fire chief and the Ecology Action Centre.
But Stop Energy East Halifax said the invite-only meetings should be open to the public.
Spokeswoman Evelien VanderKloet said other people affected by the project, including First Nations groups and property owners along its route, should be included.
"We see this pipeline as a bigger pubic issue because of the extreme impacts that's it's going to have on climate change," said VanderKloet.
But the National Energy Board said it hasn't ruled out holding public meetings in the future. Spokesman Tom Neufeld said organizing public meetings across the country is costly and time-consuming and the board wasn't sure at the outset if there was enough public interest.
"Quite frankly, we just didn't know if people would come," said Neufeld. "We thought the best way to contact Canadians that really are impacted directly by our work was to call them directly and ask for meetings.
"But if there's interest ... we just might have them."
Many groups have asked to be invited to the meetings but Stop Energy East Halifax has not, he said.
"Quite honestly, if they contacted us, we would try and fit them in the schedule."
Neufeld said board officials will meet with First Nations groups and property owners along the pipeline's route will either be met with directly or will be represented by political leaders such as mayors.
"We're willing to meet with Canadians in their kitchens," he said, adding they have such a meeting in New Brunswick later this week.
Neufeld also encouraged the public to provide feedback about the pipeline on the board's website.
Follow (at)Aly Thomson on Twitter.