A toxic spray linked to causing cancer in humans could be eliminated from Tauranga's parks and reserves.

The city council has taken the first step towards finding alternatives to the agrichemical weedkiller glyphosate - the active ingredient in commercial brands such as Roundup.

Councillors agreed unanimously to trial a mixture of pine oil and fatty acids as an alternative to glyphosate, to kill weeds on selected walkways and neighbourhood reserves. The fatty acids contain plant-derived agrichemicals.

Yesterday's meeting of the council's strategy and policy committee also decided to investigate the use of hot water or steam as another alternative to glyphosate.

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The decision was supported by members of the council's toxic agrichemical advisory forum who attended the meeting.

Forum member Dr Ron Lopert urged the council to adopt the path taken by 12 countries, including Germany and Mexico, to ban the use of Roundup, saying there was enough scientific evidence to show it was a probable human carcinogen.

He said the toxic effects impacted on lungs, the reproductive system, the brain and nervous system, the gut, and DNA and chromosomes.

"More and more countries are moving to ban or restrict its use."

The latest authority to ban its use was the California Environmental Protection Agency, which said it would list glyphosate as a substance known to cause cancer.

The council agreed that it would review its use of glyphosate once the New Zealand Environmental Protection Agency delivered its findings on the agrichemical.

A report to the meeting said that the World Health Organisation recently classified glyphosate as a "probably carcinogenic," following a study by the International Agency for Research on Cancer, with experts from 11 countries.

Councillor Matt Cowley said there was public pressure to reduce toxicity. There was a balance between cost and effectiveness and the council was on the right transition. "We are looking at alternatives and what we are proposing is right on the button."

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He said it was a practical response that looked forward to reducing and one day eliminating the use of glyphosate.

Corporate and policy planner Melony Atkins said the additional cost of replacing the much cheaper Roundup with alternative weed control measures would be $200,000-plus a year.

Councillor John Robson said he appreciated the issue more than anyone else because of his personal politics, but it would be difficult to whack an additional $200,000 into the budget.

The trials over the 2015-16 growing season meant the council would not be in a position to go out for public consultation next year on the additional costs to replace Roundup.

Mayor Stuart Crosby said there was growing evidence that glyphosate was against the public safety provisions of the council's vegetation management policy.

"I am swayed by the large number of countries that have gone through their own research."