The truck driver was confronted at a gas bar along Route 116 during the lunch hour, police said, referring to it as a peaceful incident.
RCMP would not confirm who owns the truck, but it has a Stantec logo on its doors. Stantec is a Fredericton-based engineering firm doing work for SWN Resources Canada, a major industry player in the province.
Elsipogtog Chief Aaron Sock had said earlier in the day his council does not welcome SWN's seismic testing in New Brunswick.
SWN spokeswoman Tracey Stephenson described the incident as a "security event" involving one the company's subcontractors.
"The safety of our employees and subcontractors is our top priority and while we cannot speak to the details of this security event we can confirm that people and equipment are safe," Stephenson stated in an email.
RCMP moved the truck to their detachment "to keep it safe."
John Levi, a warrior chief in the community, then parked his truck behind the Stantec truck, blocking it in.
Officers were speaking to Levi and a couple of other men, as about 20 other people milled about outside.
RCMP are monitoring the situation, which remains peaceful, Cpl. Chantal Farrah told CBC News.
"As police, we support anyone's rights to hold a peaceful and lawful demonstration, but things need to remain peaceful and lawful," Farrah said.
"That is very important and for us as a police agency. We have to balance our security operations with individuals' rights and freedoms in order to maintain public safety, peace and good order," she said.
It's unclear how long the Stantec truck will remain at the RCMP office.
Meanwhile, an aboriginal consulting firm in the province is supporting SWN Resources Canada and its seismic testing program in Kent County this summer.
Chief to Chief Consulting Group has been hired by SWN to monitor its work as it continues exploring for shale gas.
Stephen Sewell, a director of the firm and a member of the Pabineau First Nation, said employees will serve as subcontractors, using their traditional knowledge of the land to protect the water, wildlife and traditional medicines.
Sewell believes SWN Resources Canada has an undeserved bad reputation that he blames on anti-shale gas groups.