An 11th person in Auckland may have contracted typhoid, health authorities say.

But the Auckland Regional Public Health Service says until the results of the latest tests are known, the official number stands at the 10 people hospitalised earlier in the week.

The cases appeared to be linked to a "common source" but work was still going on to confirm the origin, it said.

"Contact tracing is continuing to allow protective measures to limit any further spread of typhoid within Auckland's Pacific community," it said.

Typhoid can be a serious illness and is potentially fatal but can be treated with antibiotics, authorities say.

Medical officer of health David Sinclair said typhoid was spread primarily through water and food but could be passed person to person.

Good basic hand-washing was one of the best ways people could protect themselves, Dr Sinclair said.

Symptoms included a high fever developing over several days, headaches, general weakness and muscle aches. Stomach pain and constipation were also common but some people would get diarrhoea.

Dr Sinclair urged anyone with those symptoms to see their doctor or an after- hours clinic.

ARPHS has alerted the health sector to the outbreak and expects to provide further updates on Monday.