A rise in confiscation of cannabis at New Zealand borders is thanks to a larger number of staff and dog teams at airports, according to Customs Minister Nicky Wagner.

Cannabis seizures at customs has nearly tripled in the last two years, with just over nine kilograms of the drug taken off passengers - and that's not including the amount that's been seized through post.

Wagner said the rise can be attributed to heightened border security.

She said the number of dog teams at security has increased and can account for much of the seized product.

"Our dogs are absolutely focused on drugs and money and we are picking up a lot more of it," she said.

Drugs aren't the only thing Customs are confiscating more of - more than five tonnes of tobacco has been seized from passengers in the 20 months following the 2014 limit change.

Wagner said people have the choice to go above the tax-free limit - but they have to pay and that's not a popular choice.

She said the majority of tobacco being abandoned or seized is cheap no-name brands.

"People are not prepared to pay the duty on something that's not quality - you see very few quality products," she said.