The Ministry of Agriculture and Forestry says New Zealand's biosecurity will be strengthened with the doubling of an instant fine for false or incorrect border declarations.
The fine will double from $200 to $400 from 22 April.
If an instant fine is contested unsuccessfully in court, MAF says the penalty will be $1000 plus court costs.
The agency says raising the fine will send a clear message to people entering New Zealand that border security is taken seriously.
Airport signage and airline information is being updated to reflect the change.