UPDATED 3.44PM: The number of people reporting cases of campylobacter in Havelock North has dropped off sharply.

It is estimated that more than 4000 people in the Hawke's Bay town have suffered symptoms such as vomiting, diarrhoea, headaches, muscle pain, and fever from drinking the town's water when it was contaminated with campylobacter bacteria.

READ MORE: Hawke's Bay water problems spread

The outbreak has forced some schools and businesses to close for almost a week.

Authorities said there were 125 confirmed cases and 351 probable cases of the gastro bug, mostly in Havelock North but there are some cases outside the town.

An interim scientific analysis indicates contamination from cattle, sheep and deer may have been present in Havelock North's water supply, which in normal times is not disinfected with chlorine.

Hastings District Council's Alison Banks said the infection rate is pretty much normal for the time of year, and hospitals are reporting it's dropped right down or there are no new incidences.

Dr Kevin Snee says there are ten people in hospital with the illness but no one is in intensive care.

"The pattern is one of the decline of the demand on services as people begin to recover and as new cases stop appearing," he said.

Dr Snee said no one has come into the hospital's emergency department with campylobacter overnight and demand on primary care has been well down.

An information tent is open again today outside the town's community centre on Te Mata Road.

Medical testing this week confirmed that 89-year-old Jean Sparksman, who had been living at the Mary Doyle village in Havelock North, contracted campylobacter before she died last Saturday. She also had other significant health problems. Her death, including any role of campylobacter, will be investigated by a coroner.

Doctors are on alert for people with campylobacter in the area developing other serious health complications, including a rare neurological disease known as Guillain Barre syndrome.

The syndrome sees the body's immune system attack nerves that control movement and feeling, and develops one to two weeks after a campylobacter infection.

Infectious Disease specialist Dr Andrew Burns said they are making sure everyone in the health system keeps an eye out for it.

"[We are] making our clinicians in hospitals, especially ED staff and the physicians and paediatricians aware there may be a case coming through in the next few weeks, and we've also tried to heighten awareness amongst our general practitioners," Burns said.

Symptoms include some tingling in the feet or fingers and hands, followed by weakness and/or painful joints, called Reactive Arthritis.

Hastings mayor Lawrence Yule will be visiting Havelock North businesses today and tomorrow as the council works on a major financial assistance package.

The council has already committed $10,000 to the Havelock North Business Association for a major PR campaign to get people back into the village.

Yule said details will be confirmed early next week on how they'll be compensating individual business owners.

"We will be meeting with businesses over the weekend to find out what is most appropriate, how that can be done and what is a fair way of doing it."