Havelock North's fever breaks

Havelock North (Getty)
Havelock North (Getty)

Legal action hasn't been ruled out over water contamination that caused a gastro outbreak affecting more than 4000 people in Havelock North.

Prime Minister John Key says it is a possibility given "someone has potentially died" as a result of the outbreak, which began more than a week ago.

Investigations are still underway to determine whether the death of a woman in a Havelock North rest home is connected with the outbreak.

"You cannot 100 percent rule out civil or criminal charges," Mr Key told RNZ on Monday. "These things can be quite serious but I'm not saying it would (lead to charges), but we have to look at everything."

The crisis appears to be winding down, with doctors seeing fewer patients and the Hastings water supply getting the all-clear.

A surprise positive test for E. coli in the Hastings supply on Saturday was down to "an anomaly due to sampling irregularities", and follow-up tests on Sunday showed the water was clean.

"The Hastings supply, which also provides water to Flaxmere and Bridge Pa, can continue to be considered safe to drink," said Hastings District Council chief executive Ross McLeod.

In Havelock North, residents should still be boiling the water before use.

"People are still required to boil their water while we put in a UV treatment plant, which should be done by the end of the week," says Mayor Lawrence Yule.

The Red Cross says though fewer are getting sick now, it still has plenty of work to do.

"We will have people available for what we call targeted outreach," says spokesman Graeme Brown, "if the council gets a call from somebody who is concerned about somebody, or somebody who needs something and they're stuck at home because they're ill."

More than 4000 people fell ill during the outbreak, caused by bacteria known as campylobacter.

The Government has confirmed an inquiry will take place to find out how it happened, and if anyone should be held responsible. The terms of reference are being worked out today.

"You've got to take it extremely seriously - thousands of people are sick - and understand what caused the issue," Mr Key told Paul Henry on Monday morning.

A broader scope will also look at the effects of agriculture and intensification after an interim scientific analysis indicated contamination from cattle, sheep and deer may have been present in the water supply.

"Like all of these things, that's the purpose of having an inquiry, to absolutely understand what's gone wrong," Mr Key told RNZ. "There's lots of potential options of what it could be."

Many businesses have struggled over the last couple of weeks, with both staff and customers sick. Mr Key said compensation is being considered, but locals shouldn't expect it to be as substantial as that offered to farmers and businesses operating in post-quake Christchurch.

"I'm pretty sure they would get through anyway. If you think about it, while it's having a massive impact, it's having a massive impact for a short period of time - it's a little bit different. Some farmers might be there years where they have no water. I'm pretty sure they'll get through it."

As of Sunday, there were only seven patients in hospital as a result of the outbreak, and none in intensive care.

An 89-year-old woman, Jean Sparksman, died during the outbreak. She had other health problems and a coroner is now investigating what caused her death.

Every school in Havelock North will be open from today.

NZN / Newshub.