Members of the Les Mills gym in New Lynn have been warned to check on their health after one of its members diagnosed with measles attended a class today.
In an email to members today, the club manager said those who have entered the premises in the past two weeks may have been in proximity or come into contact with the infected member.
"We've just found out that unfortunately one of our members who attended a class today has been diagnosed with measles," the club manager said in an email.
"Obviously, this is part of the serious outbreak currently in the greater Auckland area.
"We're contacting you as you have attended the club during the past two weeks, and may have been in proximity to the affected member.
"We urge you to contact your health professional should you suspect any illness. The Auckland Regional Public Health Service recommends that if you are concerned about measles you should call Healthline on 0800 611 116 or call your GP.
"Please do not just turn up to your GP, after hours or emergency department as you could potentially infect others. Please stay safe."
The warning to Les Mills New Lynn members comes the same day it was announced another 39 measles cases were confirmed in Auckland as the city teeters on the edge of an epidemic.
Measles has been rapidly spreading after 37 new Auckland cases were also confirmed on Tuesday morning and 126 in the eight days before that.
The total number of city cases this year now sits at 585, Auckland Regional Public Health Service said.
ARPHS public medicine specialist Dr Maria Poynter earlier warned it was a "very serious outbreak".
She urged anyone aged between 1 and 50 years old to make sure they had at least one measles vaccination, given just one shot would protect 95 per cent of people from the disease.
It comes as nine out of 10 people who contracted measles this year had not been vaccinated or didn't know their vaccination status, new figures by Government agency, the Institute of Environmental Science and Research figures, showed.
Children have been hit particularly hard.
There have been 87 cases in 50 schools across the Auckland region since the start of the outbreak as well as 63 cases in 36 early learning services.
A public health service spokeswoman said the numbers of children hit by measles didn't reflect just how much disruption the disease was causing.
Every time a person is found with measles at a school, all unvaccinated students and staff members who were in the same class, team or school group as the person must spend one to two weeks in quarantine.