Bay health official have registered three cases of the Zika virus in the past 12 months.
Toi Te Ora Public Health Service confirmed that following a reported case in March last year, two further cases were notified to the service this year.
One patient lived in the Western Bay region and the other from the Eastern Bay of Plenty.
Last year's case related to a man who had traveled to Vanuatu.
The latest cases involved two women, one who visited Tonga in February and the other who traveled to Fiji this month.
The Zika virus is spread mostly by the bite of an infected Aedes species mosquito not normally found in New Zealand - currently there is no vaccine to prevent or treat Zika.
Zika virus infection usually results in a relatively mild illness, and symptoms included a low grade fever, joint pain, muscle pain, headache, red eyes, and a rash.
Medical Officer of Health Dr Phil Shoemack said the concern was that Zika virus has spread to countries such Brazil, which had not previously reported cases.
"Our concern is that recent research by the World Health Organisation confirms that when a woman contracts the Zika virus infection during pregnancy, there is risk it can cause birth defects in the baby."
There has also been three reported cases of Dengue fever this year, again involving people who had returned from overseas trips, he said.
The symptoms of Dengue Fever are similar to the Zika virus.
Dr Shoemack urges travelers to seek medical help if feeling unwell with 10 days of their return from an overseas trip.
An anyone was considering travelling overseas was urged to go online and check out the Ministry of Foreign Affairs' SafeTravel advice at www.safetravel.govt.nz/Travel Safe advice.