Samoa's Ministry of Health has confirmed a case of whooping cough, or pertussis.
New Zealand has declared an epidemic of the disease.
The health ministry said a seven-week-old baby boy, who had not yet received any vaccination, was confirmed to have whooping cough earlier this month and has since recovered.
The ministry said it continues to observe a high number of severe acute respiratory illnesses presenting to the hospitals.
"Moreover, other countries in the Pacific have reported increasing cases or ongoing circulaiton of pertussis," the Ministry said.
"It first starts off like the common cold with mild fever, runny or stuffy nose, which in most cases develop into a hacking cough followed by a whooping sound at the end of the coughing fit."
The Ministry said vaccination in line with the immunisation schedule is the best prevention.
"The best way to prevent whooping cough (pertussis) is through timely vaccination of infants with a pertussis containing vaccine, in line with the immunization schedule.
"In Samoa, infants are vaccinated with the pentavalent vaccine (pertussis/whooping cough, diphtheria, Hepatitis B, haemophilus influenza and tetanus) at 6 weeks, 10 weeks, 14 weeks and DPT (diphtheria, pertussis and tetanus) vaccine at 15 months."
However, vaccines for adults and children over seven years old, including pregnant women, are not yet available in Samoa.
In Aotearoa, health agencies declared a whooping cough epidemic on Friday, after 263 cases were confirmed in the previous month, and have warned vaccination rates are too low.
Immunisation Advisory Centre founder Nikki Turner said there was no quick fix, but people should get vaccinated now.
"The epidemic is probably going to continue long and slow. It's going to last 12, probably 18 months," she said.
"What we need to do is to protect as many most vulnerable people as possible from it.
"It's highly infectious - way more infectious than Covid. If you're standing in a room you can spread it to everyone."