A new border clearance tax that takes effect today will help to protect the country from pests, Customs Minister Nicky Wagner says.
Air travellers will pay $21.57 for a return trip, while cruise passengers and those arriving on private boats and planes will pay $26.22.
All travellers are a risk, because they can inadvertently carry pests, Ms Wagner said.
It might be a fruit fly on an apple on a cruise liner, or something stuck on the bottom of a person's shoe.
The levy rate will be reviewed after two and a half years.