Rocket Lab says it has found the reason a battery overheated on its assembly line and has put corrective measures in place.

Firefighters were called to the company last night after the manufacturing area was affected by smoke from the lithium battery.

They are made by Rocket Lab, which uses batteries to drive its turbo pumps in its engines rather than complex and expensive gas generators.

''The launch vehicle, including the engines, suffered no damage. The damage was limited to the battery only and it was caused by an installation issue which has been rectified,'' said founder and chief executive Peter Beck.


''It's business as usual today in the production facility and we're still tracking well with preparations for our next launch.''

Three fire engines and 16 firefighters attended the incident. Nobody was injured.

''Naturally, when a rocket company calls the fire service, they come prepared with a full response which meant several appliances attended,'' said Beck.

Firefighters remained on site for several hours to ensure the batteries were safely cooled.

Rocket Lab successfully reached orbit in January and details of its next flight will be made available in the next few weeks.

The battery incident happened a day after a group of United States Congress members visited the plant near Auckland Airport.

The company is registered in the US but has most of its operation in this country, including a launch range on the Mahia Peninsula.

Lithium batteries have caused problems before in aerospace. Soon after Dreamliners began flying commercially they were grounded after smouldering battery problems. They were resolved by more stringent controls over battery manufacturing, installing fire-roof housing and venting systems on planes.