Local Government New Zealand is to lobby Parliament to help councils shoulder more of the cost of upgrading drinking water supplies.
The Government has given councils three more years to meet the requirements of the Health Amendment Act which was passed under Labour in 2007.
Communities with more than 10,000 people originally had until July to finalise plans for required improvements.
Local Government New Zealand says 20% of councils would have struggled to find the money needed in such a short timeframe.
It says the former Labour Government estimated the upgrade would cost up to $250 million nationally, but the bill could be double that.
LGNZ president Lawrence Yule says central Government already provides some help, but more will be needed.