Christchurch Council has completed its review of glyphosate, and has decided to reduce its use of the highly effective weed killer that has been shown to be safe. There is currently a global campaign against the chemical - fueled by the fact that it is sold by Monsanto as RoundUp, with Monsanto also creating crops that are resistant to the chemical.

Earlier this year Christchurch estimated that switching to using fatty acid weedkillers and manual weed pulling will cost an extra $5 million per year.

The new estimate is:

$2m already budgeted this year, plus another $1.8m. $6.1m set-up cost spread over three years"

The decision is based on an IARC cancer rating that glyphosate has been given is very low. Dr Kerry Harrington, a senior lecturer in weed science at Massey University, said it is akin to:

"burning wood in the fireplace at home, upsetting circadian rhythms by doing shift work, or being a hairdresser. It is not a high level of risk. Should we ban all shift work or stop people burning wood in their fireplaces?"

Steffan Browning of the Green Party (of homeopathy for ebola fame) has called for other councils to follow Christchurch and move to more costly, less effective methods of controlling weeds.