Associate Health Minister Sam Lotu-Iiga says it's possible heads might have to roll at Hastings District Council, following Havelock North's gastro outbreak.
More than 2000 people have come down with violent vomiting and diarrhoea since the Havelock North water supply was contaminated with campylobacter last week.
Schools across the town are shut, and it's still not clear how the bacteria got into the water.
Mr Lotu-Iiga says terms of reference for an inquiry are currently being developed to find out how the contamination happened and who, if anyone, is responsible.
"I don't think it's for me to prejudge that inquiry, but mistakes have been made," he told Paul Henry on Wednesday.
He's not ruling out sackings over those mistakes.
"We can't make that call right now. Certainly, they should be held to account… that's one of the options."
Growers are desperate to reassure the public it's safe to eat fruit and vegetables from Hawke's Bay, despite the region's contaminated water supply.
Horticulture NZ, which represents the produce industry, says it's definitely not in the region's food supply.
"You need to have a fruit cut open… and for contaminated water to touch the cut-open bit of fruit for there to be a problem," says chief executive Mike Chapman.
"It's a long, long, long stretch for anything to be of concern to the public."
However, many growers in the region are holding off on picking their crops as a precaution.
"Even if [they were], there are no risks because of the food safety systems we have," says Mr Chapman.
Of those that are picking, like schools they're struggling with low staffing levels.
"The remaining staff just have to step up and fill in the gap," says Hamish Davis from apple exporter Fern Ridge Produce.
"But it's just a bit of an annoyance and something that should have been avoidable."
The Ministry for Primary Industries is working with the Hastings District Council to contact local businesses, making sure they're aware of food safety measures. The Ministry of Health is also on the ground.
"Support services are out there, calling up people and door-knocking to ensure that people have got the message around the water supply," says Mr Lotu-Iiga. "It hasn't been good."
The council is considering compensation for any businesses hit in the pocket by the outbreak.
The Greens say dairy farming needs to be seriously considered as a possible cause of the gastro outbreak.
Co-leader James Shaw says the party has been worried about something like this for a long time.
"We've often said that intensive dairying and other intensive forms of land use can lead to pollution of groundwater, and make its way into the water supplies of townships. That is a real possibility, that is a real threat."
But he doesn't want to play the blame game until a full investigation has been completed.
"I think if you talk to the people of Hawke's Bay right now they'll be very concerned, and they'll want an absolutely thorough investigation to see precisely what's happened. I think people all over the country will be really concerned it could possibly happen to them as well."
Seventeen people remain in hospital, two of them critical.
Dr Nick Jones says more nursing support has been provided to rest homes, which are reporting increased illnesses.
With the amount of illness still present, Dr Jones is urging people to continue to be vigilant about hand washing before and after preparing food, after going to the toilet or changing a baby's nappy, after caring for people with campylobacter and after contact with animals.
While campylobacter can't be spread through the air, it can be spread by swallowing the bacteria, through either contaminated water and food, or contact with infected people.