The sub-variant, also known as Kraken, was descended from the Omicron XBB subvariant, itself a cross between two earlier strains: BA.2.75 and BA.2.10.1, Radio New Zealand Pacific reports.
It comes just a day after New Zealand said the variant had also been detected in the country late last week.
The World Health Organisation said it has been detected in at least 31 other countries.
Medical superintendent Jemesa Tudravu told FBC news the variant had high transmissibility.
"It is a known variant that has high transmissibility and so we are also undertaking our monitoring of variants and testing of other variants for the positive cases that may have come through."
Tudravu said he knew there were other variants in the community which were equally transmissible, which the Health Ministry was currently tracking.
