School holiday travellers are being reminded to be vigilant against measles.
Six confirmed cases of the infection are in the South Island, but officials warn even being near an infected person puts you at risk.
- Canterbury DHB on the hunt for measles 'patient zero'
- Two new measles cases as disease spreads in South Island
Dr Caroline McElnay from the Ministry of Health says there's one way to guarantee protection.
"If your children aren't immunised, this is a reminder the vaccine is very safe and it's very protective against measles. It's worth considering getting that done now, at the beginning of the holidays."
The Ministry of Health says vaccines are free for anyone who needs it, as are doctor's visits.
But Dr Caroline McElnay says if you think you've already contracted it, avoid people altogether.
"Please just don't turn up to your GP or emergency department - ring up beforehand. Because measles is so infectious, you can pick up measles by sitting in the same waiting room."
She says the illness might strike when you least expect it.
"You get secondary cases occurring from being in the vicinity of someone who's infectious with measles."
The sixth case has prompted a fresh warning for people who travelled between Queenstown and Christchurch on Air NZ flights a week ago.
Officials say anyone who travelled on flight NZ5642 to Christchurch, or NZ 5653 to Queenstown, may have been exposed.
Symptoms don't show up for around 10 days, but include a cough, sore throat, and a fever.