WATER bombers have been used to help contain a grass fire in the Adelaide Hills.

It is thought the fire started in a hay baler being used by a farmer on his Paracombe property about 11.15am.

AdelaideNow reports six Country Fire Service units and two fire bombers contained the fire after it had burnt about half a hectare.

Emergency service spokeswoman Nicole Ely said "fire crews are continuing to monitor the situation".