However, Mr Warren said the first priority should be removing any bacterial risks in drinking water, and chlorine remained the cheapest way to do that.
The Cancer Society said there was only a very tiny risk of chlorinated water causing cancer.
Cancer Society medical director Dr Chris Jackson said there was a study done in New Zealand in 1998 which found a very weak link between people who smoked cigarettes and the long-term consumption of chlorinated water, where they risked getting a very rare cancer.
However, he said, the number of people in that risk category would be very, very low.
Dr Jackson said the dose of chlorine in the water in Havelock North and Hastings would be too minimal to present a risk.
Pure chlorine and its related products may be carcinogenic, but the levels used in public water supplies are very low and don't unduly raise the risk of cancer, he said.
Hastings Mayor Lawrence Yule would prefer to have chlorine-free water in the future.
He said Hawke's Bay was known to have some of the best water in the world and people would like to keep it that way.
His preference was that the council did not chlorinate the water in the long term and that it find a rigid, more extensive testing regime so water was tested more regularly than it had been.
- Newstalk ZB
