Ten people have been hospitalised with typhoid in Auckland.

The Auckland Regional Public Health Service (ARPHS) has confirmed the outbreak and says it's tracing people who have been in contact with those who have been infected with the disease and "following usual protocols" to stop it spreading further.  

Medical Officer of Health Dr David Sinclair said it was unclear how the outbreak started.

"We're trying to work that out. We've got some clues but other things we haven't sorted out yet, so that will take a little while to sort out yet.

"But in general typhoid is imported. It comes from people returning to New Zealand from the Pacific or from South East Asia."

Shellfish sourced from sewage-contaminated beds have caused earlier outbreaks in New Zealand, the Ministry of Health website states. 

Flies can also spread the bacteria to food, but most large epidemics are caused by faeces contaminating water supplies.

About 20 to 30 people are diagnosed with typhoid every year in New Zealand, so to have an outbreak of 10 infections in such a short period was concerning to public health officials, Sinclair said. 

"The last significant outbreak in Auckland was in 2013." 

He told the Herald public health officials first became aware of the outbreak when the first patient was admitted to hospital at the end of last week. 

The other nine people confirmed to have the infection were hospitalised this week. 

The patients were believed to be locals rather than tourists, he said. 

Sinclair was unable to confirm the condition of the people who had been hospitalised.

Good hand-washing is the best protection against the serious illness, which is mainly spread through water and food but can also spread person to person.

The potentially fatal disease can be treated with antibiotics.

Symptoms to look out for were a high fever developing over several days, headaches, general weakness and muscle aches. Some people infected with the disease also get stomach pain, constipation or diarrhoea.

Sinclair advised anyone feeling very unwell to see their doctor or an after-hours clinic.

ARPHS has notified the medical sector of the outbreak. 

According to the Ministry of Health's website, people with the disease usually present symptoms eight to 14 days after being infected.

The bacteria that causes typhoid is found in the stools of about 10 per cent of untreated patients for more than 3 months, and 2 to 5 per cent of those infected who aren't treated for typhoid become permanent carriers.​

- NZ Herald