The New Zealand government could use a new public interest test to identify overseas dumped products and subsidized goods, New Zealand Commerce and Consumer Affairs Minister Jacqui Dean said on Wednesday.

The Trade (Anti-dumping and Countervailing Duties) Amendment Bill, which introduces the new public interest test into the anti-dumping regime, has passed its final reading Wednesday.

"The public interest test will weigh up the benefits of at-the-border duties on dumped products and subsidized goods, which are aimed at protecting domestic manufacturers, against the wider benefits to the public of cheaper goods in important industries like new home construction," Dean said.

Goods are considered dumped if the export price to New Zealand is less than the price they are sold for in their home market. A duty can be imposed on those unfairly priced goods if they are harming competing New Zealand manufacturers.

Countervailing duties can also be imposed when New Zealand manufacturers are being harmed by competing imports that have been subsidized by a foreign government.

The bill also extends the suspension of anti-dumping duties on residential building materials until June 30, 2019.