Health New Zealand says it's likely that measles is circulating in the Wellington community.

This came as it confirmed a new case in the capital, bringing the total number of known cases to four.

Health NZ said its investigations were continuing, but the case was not currently linked to any already named locations of interest.

A third person was identified with the illness last week, prompting a call for people who dined at a Newtown restaurant to watch out for symptoms.

Health NZ said the third case was linked to a person who dined at Mediterranean Foods Trattoria and Deli in Newtown while infectious on April 19.

"We encourage people to check their immunisation status and to keep an eye out for symptoms of measles, including fever, cough, runny or red eyes, and a rash starting at the face," said Dr Emma Sherwood from Health New Zealand's National Public Health Service.