People who recently flew from Perth to Auckland are being advised to monitor for whooping cough symptoms after two passengers from a flight became confirmed cases.

Te Whatu Ora said the passengers were on flight OD195, arriving in Auckland on Monday, 28 August.

This risk for most passengers was considered low - but those who were in rows 8 to 12 were considered high risk of catching whooping cough and are being treated as contacts.

"These people should be particularly alert to symptoms, and request antibiotics from their GP if they are pregnant, have a baby under 12 months old, are immunocompromised, or live or work with any of these groups (even if they do not have symptoms)."

The confirmed cases from the flight were receiving appropriate medical care, Te Whatu Ora said.

"The cases were notified to Te Whatu Ora by the Australian government, as per standard international infectious disease protocols."

Medical officer of health Dr Michael Hale said whopping cough was particularly dangerous for babies, young children and pregnant people.

"While the risk for most passengers on the flight was low, we are keen to make sure those who could become very sick from whooping cough are alerted to the risk and know the signs to look out for."

Te Whatu Ora said there have been 69 cases of whooping cough so far this year, including three deaths in infants.

Whooping cough symptoms include a runny nose, fever and cough. They can develop anytime in the two to three weeks after exposure.

Those on the flight are asked to:

• call their doctor or usual health care provider for testing and treatment;
• stay away from those who are pregnant or have babies if they are unwell with any sort of respiratory (breathing) illness symptoms until they've spoken to a doctor;
• seek urgent medical advice if they have difficulty breathing, by calling 111.

Hale said immunisation is the best protection against the illness.

The whooping cough, tetanus and diphtheria vaccine is free and offered:

• to children at 6 weeks, 3 months and 5 months old, with boosters also offered at 4 and 11 years old;
• from 13 weeks of every pregnancy (consider booking between 16 and 26 weeks of pregnancy as this is when the vaccine is most effective);
• for some people aged 45 years old (if they have received fewer than four tetanus doses in their lifetime);
• for everyone from 65 years old if it has been more than 10 years since a previous dose of tetanus and diphtheria vaccine. If you have already had a free tetanus and diphtheria vaccine from age 65, you will not be eligible for a free Boostrix vaccine.