Metgasco says it received a bomb threat at its Casino office earlier this week after a man walked into the building and threatened staff.
According to The Northern Star, Metgasco said the office received a call around 1pm on Monday from a man who threatened to blow up the building.
"Tell [Metgasco managing director] Peter Henderson that there is a bomb in the office and we are going to blow all your heads off," the man allegedly said.
Metgasco said the call followed an incident earlier in the day where a man had entered the office and threatened staff with an umbrella.
In response to the incident the Australian Petroleum Production and Exploration Alliance called for calm.
Henderson also said the anti-coal seam gas movement was not peaceful and Metgasco workers and government officials had previously been threatened and abused.
While the APPEA has called on protest groups to condemn the action, CSG Free Northern Rivers spokesperson Annie Kia told The Northern Star the incident could have been a hoax.
"We don't even believe this was real … we have noted a pattern of exaggeration and distortion coming from Metgasco's PR," she said.