Marine Atlantic ferry Atlantic Vision returned to port in North Sydney Wednesday morning after a fire broke out in a boiler room. (CBC)

A Marine Atlantic passenger ferry heading to Newfoundland returned to North Sydney, N.S., on Wednesday morning after a fire broke out on board.

Fire was reported in the Atlantic Vision's thermal heating unit shortly after it set sail for Port-aux-Basques at 6 a.m. AT. It returned to port an hour later.

The fire, which was confined to the boiler room, has since been put out.

"I woke up to an alarm and it took me a few minutes to figure out what was going on," Lori Savery, a passenger aboard the ferry, told CBC News on Wednesday. "I smelled something that didn't seem right."

Savery said she got out of her bunk and went outside when she heard an announcement from the captain saying they were returning to port due to smoke aboard the vessel.

"I felt just nervous being in the middle of the gulf and not knowing really what's going on," Savery said.

A spokeswoman for Marine Atlantic said there have been no reports of injuries. All 626 passengers were safely taken off the ferry.

"Everybody’s safe," Tara Laing told CBC News on Wednesday. "The captain... made a number of announcements to the passengers to let everyone know what’s happening."

Marine Atlantic said the MV Atlantic Vision will be out of service for at least 24 hours. The ferry passenger service will not be accepting any new reservations while they clear up the backlog of travellers.

The Argentia crossing was cancelled for Wednesday. The MV Joseph and Clara Smallwood, as well as the MV Caribou, were operating on quick turnarounds between Port-aux-Basques and North Sydney.

Commercial traffic has been restricted to the MV Leif Ericson for the next 24 to 48 hours.

Police try to co-ordinate car traffic

Meanwhile, police were trying to co-ordinate vehicle traffic that began to back up Wednesday afternoon.

"The trucks are being turned away from the booths," RCMP Sgt. Ron MacDonald said. "They're being given a sequential number and asked to go away until further notice, until they're phoned by Marine Atlantic people, and that's certainly causing some frustration.

"Right now, we're trying to get them to a safe place. They're on the ramp leading out of the Marine Atlantic terminal, and we're just talking to them right now, trying to get them to safe and convenient location," MacDonald said.

It’s the second time that a fire has broken out in the Atlantic Vision's thermal heating unit. The last fire occurred in December 2008 before the vessel was put into service.

Atlantic Vision is the newest passenger ferry in Marine Atlantic's fleet. Dubbed the "super-ferry," it was delayed for more than five hours on its inaugural voyage across the Cabot Strait on April 1 while loading tractor-trailers in North Sydney.

The support legs at the bottom of one tractor-trailer jammed on the loading ramp the night before it was to depart for its first crossing. Equipment had to be brought in to release the truck before the ferry could leave Cape Breton.