Waikato Regional Council's new pest management plan, which tidentifies 150 pests, does not necessarily mean an increase in the use of poisons, spokesperson Kevin Collins says.
The council passed the new plan only on the casting-vote of its chairperson, after some councillors expressed concern that more poisons would be used, but councillors have reserved the right to make changes to the plan at a later date.
The control of pests is one of the most expensive parts of the council's work.
Mr Collins, the council's natural heritage programme manager, said the council was required by law to think about the consequences of pests coming in and that may require the use of toxins.
"The reality is that toxins are not the only way to control pests. We use a lot of bio-controls and in some cases the toxins are becoming much more specific, so instead of using a broad-spectrum herbicide you use something that's much more targeted," he said.
"We're conscious that herbicides and other toxins can be damaging if they're used in the wrong way, but that applies to lots of things, so on the whole the conclusion is that controlling these most serious pests is a benefit."