CREWS fighting a "ballistic" fire in Crediton may have saved more than a dozen houses.

QFES Kippa Ring Fire Station Officer Ross Nunn said Thursday night that he and his crews had been fighting fires along Cathay Creek Road, at Crediton, for more than six hours.

Mr Nunn, who has come from Brisbane to reinforce local firefighting crews, estimated that 10 fire crews and a number of water trucks had worked non-stop to save more than a dozen houses.

Overhead fixed wing water bombers were seen dropping tonnes of water onto the Crediton fires for most of the day.

Mr Nunn said conditions worsened from midday as the wind changed throughout the day.

He said at 3pm the fire was doing "really silly things".

"It was one of those really bad fire days where nothing went to plan and everything went wrong," he said.