Yarrow Stadium's light configuration was to blame for the dimness during Friday night's National Provincial Championship match.

In the first night game under the new LED floodlights, there were shadows across the field with dark patches in the middle of the ground, obvious to those watching on television and at the ground.

Taranaki Regional Council director corporate services Mike Nield said the current lighting configuration, which was tested before the match, was wrong and the light distribution caused the shadows.

"The floodlights are designed to work with lights which will eventually go on the West and East stand's roof," he said.

"We apologise if this affected people's enjoyment of the game on Friday."

Nield said the lights were still running above the broadcast standard illumination level of 500 lux. During the match, the regional council, which owns the stadium, was working with tenants Taranaki Rugby and broadcasters Sky Television.

Given the stand lighting would ordinarily mitigate the shadows, contractors were working on improvements to the programme for Wednesday night's match between Taranaki and Counties Manukau.