The government has banned the sale of small, high-powered magnets saying they can cause serious harm if children swallow them.
Consumer Affairs Minister Simon Bridges says Australia banned the magnets after the death of an 18-month-old child in Queensland and the United States has taken similar action following children being hospitalised.
In New Zealand, a toddler was admitted to Auckland's Starship Hospital in December after swallowing some of the magnets.
Mr Bridges says the magnets are sold all over the world in sets, described as office toys and aimed at the adult market.
"Though many brands carry strict safety warnings, it is clear from the cases here and overseas that they pose too great a risk to children," he said.
The magnets are 50 times stronger than conventional ferrous magnets and can join up in a child's stomach if they are swallowed, causing inflammation and ulceration.
The notice Mr Bridges has issued under the Fair Trading Act bans the sale and import of the magnets from Thursday.