MetService says a ball of fire seen in the sky over Wellington this evening shouldn't be a cause for concern.

Witnesses in Hataitai say the streak of light looked like a meteor or asteroid.

But MetService duty forecaster Leigh Matheson believes it was the contrail of a long-haul aircraft which was due to fly over the city at around that time.

"The lights that were seen over Wellington, we believe, was the contrail of a long-haul aircraft that was flying across the country," Matheson reports. "Around 5.30 in the evening the setting sun lit the contrail up quite brightly."