A 14-year-old high school pupil has been suspended after being caught dealing in the legal synthetic cannabinoid substance Kronic.

Hutt Valley High School principal Ross Sinclair confirmed that he had suspended a year 10 pupil for two separate incidents that happened late last month.

He would not go into details but said they involved an offer to sell Kronic to a pupil at school, which was rejected, and supply of the product on the way home.

While it was not illegal for the pupil to be in possession of Kronic, the board of trustees had the power under the Education Act to ban it. "You can't have kids supplying mind-altering anything to other kids: it's not going to get them anywhere."

Kronic is made of vegetable matter sprayed with chemicals that mimic the effects of cannabis.

Secondary Principals' Association president Patrick Walsh said it was the first time he had heard of a pupil being suspended for dealing in Kronic but he knew it had become a problem at many schools. Several principals had raised concerns at forums; they had reported pupils going to sick bays with symptoms including nausea and vomiting.

A lack of dosage information meant some were consuming high amounts, with one pupil smoking three Kronic joints in an hour, he said.

Consuming the substance outside school hours with alcohol was also a problem, and some were driving after smoking it because it could not be detected by police.

The association met Education Minister Anne Tolley and ministry officials two weeks ago to raise their concerns.

Mr Walsh said the current law that allowed the product to be sold when it had not been tested as safe for consumption was "perverse and absurd" and he hoped a law change would be introduced soon.

Mr Sinclair also said he would like to see more restrictions around synthetic cannabinoids.

Mr Dunne said additional changes to the Government's bill would be the first item of business when Parliament resumed on August 2 and would be an interim step before the Government could legislate to make the industry prove its products were safe before being sold.

Matt Bowden, whose company Stargate imports the ingredients used in synthetic cannabis products, agreed the amendments to the current act were a stopgap and he encouraged the Government to move quickly towards introducing better regulatory controls.

"Rigorous regulation will keep the cowboys out of the industry and establish high standards. I am strongly in favour of establishing such standards. They will ensure consumers can choose from a range of safe products."

Matthew Wielenga, owner of the Kronic brand, did not return calls.

* This story has been updated since first published.