Seen some K2 on store shelves? An 0800 psychoactive substance hotline for people to report concerns about legal highs was launched by the Ministry of Health on Thursday.
Some retailers had already been dobbed in by members of the public, said Todd McClay, Associate Health Minister.
He said legal high shops had been closed and prosecutions had been made under the Psychoactive Substances Act.
One retailer had recently been arrested in Hawera after breaching the Act.
"This information was passed on to the regulator who quickly suspended the retail licence, taking legal highs off the shelf," said Mr McClay.