According to eye-witness reports, firefighters attended the scene after the alarm was raised in one of the projection rooms.
Cahal Elliott, who was asked to leave the cinema after 9pm, tweeted: "Projector fire tonight... red lights flashing during film."
Reader Aine Monahan wrote "evacuation from Omniplex" and tweeted impartialreporter.com a photograph (right) of a fire appliance outside the building.
And Katie Benson from Lisnaskea tweeted: "So the first time I have been to the cinema in like a year and what happens... the fire alarm goes off and everyone's evacuated."
It's understood the cinema was reopened a short time later.