Clean-up crews looking into a diesel spill in Kawhia Harbour yesterday will focus their efforts on finding who is responsible.
Concerned locals complaining of the strong diesel smell and a large sheen across the harbour called authorities about 1pm yesterday.
At its largest point, the sheen spread 50m by 70m, but Waikato Regional Council on-scene commander Adam Munro said the areas impacted by the spill - estimated to be at least 100 litres - was "not a huge area".
"It looks like with the tide going out and the wind going in the same direction the concentrated oil would have gone out over the entrance and conditions for breaking it up are quite favourable," he said.
"We were talking about 100 litres at this stage and oil and water always looks more than it actually is. But obviously the locals were concerned because there was a heavy smell in the air."