FREDERICTON - New Brunswick NDP Leader Dominic Cardy says the president of a Calgary-based energy firm tried to muzzle him.

Cardy says Khalid Amin, who heads Windsor Energy, called him Wednesday and threatened a lawsuit if he didn't stop saying that the company broke provincial regulations in its search for shale gas.

"He proceeded to tell me off for having had the temerity to say exactly the same thing as pretty much everyone else in the province has been saying," Cardy said Thursday.

The provincial government has said the company conducted seismic testing along a highway inside the town of Sussex without municipal permission in October.

The government filed a complaint with the RCMP, alleging Windsor Energy violated provincial legislation, but the Mounties dismissed it.

Cardy said Amin's call took him by surprise.

"He was saying I didn't have all sides of the story which I thought was interesting because when I asked him what the other side of the story was, he wouldn't tell me," Cardy said.

"He just repeated his previous statements that if I didn't stop criticizing him that he'd slap a lawsuit on me."

Cardy accused Amin of "trying to stop the press and the politicians from telling the truth about the industry."

Amin did not respond to an email request for an interview, and a phone number for the company's Calgary office was disconnected.

In a Nov. 3 letter to Natural Resources Minister Bruce Northrup, Amin apologized for instructing contractors to proceed with the seismic testing.

"It was our decision to proceed, and it was the wrong one," Amin said. "We should have awaited the outcome of the Sussex council meeting. Upon reflection, we now understand why you and the community leaders are upset."

Windsor Energy's lease for exploration expired on Nov. 12 and the company has until Feb. 12 to show they have met all the criteria for a new lease.

Cardy said the government needs to deny any request from the company for a new lease.

"We do not need Windsor Energy in New Brunswick," Cardy said. "The government has got to tell them to get lost."