Prime Minister John Key has said charges could be laid after the gastro outbreak in Havelock North and Hastings.

More than 4000 people are thought to have been struck down by Havelock North drinking water contaminated with campylobacter.

Key is backing the Hastings District Council, saying it acted as quickly as it could.

But he told Newstalk ZB's Mike Hosking there could be court action, as it's not clear whether the contamination contributed to the death of a woman in a rest home.

He said that court action could involve civil or criminal charges.

Key said people still need assurance things were done properly and the terms of a government inquiry into the incident will be discussed in cabinet today.

Labour's Napier MP Stuart Nash said it's hard for locals to trust the water infrastructure again, when it's still so unclear what went wrong.

He said they don't need anyone to blame, just answers on what to do next. 

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