Anti-chemical groups are urging Auckland Transport to ditch its use of the weed killer Round Up, citing its links to cancer.
The board was presented with a petition today which make reference to health concerns relating to the herbicide's primary chemical, glyphosate.
Early this year, the World Health Organisation published a study showing the chemical is a probable human carcinogen, with animal testing linking its exposure to cancer.
Roundup is the world's most widely produced weed killer, but several countries have made moves to ban its use, most recently France and The Netherlands.
In Auckland, the chemical is used to spray road pavements in urban areas and for vegetation control in rural parts.
Auckland Transport said this was in compliance with the council's Weed Management Policy, and the New Zealand Standard for Management of Agrichemicals.
But the community groups fighting for it to be banned are not convinced.
Meriel Watts, from the Weed Management Advisory, said the council's policy called for minimising agrichemical use, not maximising it.
She said the continued use of glyphosate was having real effects on residents.
"There's a whole range of issues - cancer is one of the major problems, but at a different level there are people who are acutely sensitive to it at a subtle level," she said.
"They get extreme exhaustion, a lot of body aches and pains, gastro-intestinal problems... there's a number of people like that within the Auckland region, and they are being completely incapacitated in their lives by this almost daily exposure."
Anti-herbicide campaigns in the 1990s in Auckland City and the North Shore successfully led to the use of non-chemical alternatives for managing weeds.
Hana Blackmore said there was no reason the same methods could not be used across the region.
"All the methods that are currently available have been used effectively... for 20 years, with hot water and vegetable based herbicides," she said.
But Auckland Transport chief infrastructure officer Greg Edmonds said the alternatives were costly and ineffective.
"Hot water does work, but it works for a very short period of time, and it doesn't kill the roots, so we have to go back and treat and treat," he said.
"While it is probably safer in terms of environmental effectiveness, the reality of it is, it's not cost effective."
He said the board ultimately relied on the Environmental Protection Agency (EPA), who continue to support the use of glyphosate.
"Let's just remember that glyphosate is used by agricultural industry all over the country, and we are eating the food and drinking the water and the milk," he said.
"There are no facts that we can find that tell us that it's unsafe to continue to use it."
Georgina Blackmore from 'Ban Glyphosate in Auckland' said that was not good enough.
"It's a very circular argument because countries around the world have already banned glyphosate, and they've done that without reference to their EPA changing their principles around it, so they've taken a precautionary measure making sure that they're doing the best thing for public safety," she said.
"Hiding behind the EPA and waiting for them to change their minds could mean many more years of people being exposed to it."
University of Canterbury toxicologist Ian Shaw said the risks should not be taken lightly.
"There's been a lot of skepticism about this very heavy use, and New Zealand is a very heavy user of glyphosate for quite some years," he said.
"My feeling is if you've got a risk of carcinogenicity, if you've got a risk of cancer, then you'd want to restrict the number of people that are exposed to it."
The Auckand Transport board has delayed its decision regarding continuing its use of the herbicide until next month.
In the meantime, it will seek to clarify the EPA's position on glyphosate and provide more information on its research.