Whanganui Police and health authorities have checked that legal highs are no longer being sold in Wanganui.
They have visited the two Victoria Ave stores that were able to sell the substances up until Thursday last week.
Senior Sergeant Paul Baskett said police ensured any unsold stock was being returned to the suppliers within the required time frame. They didn't find any breaches of the new law, and didn't anticipate any.
They also checked that those stores had security measures, in case a user of the substances tried to rob them.
The Whanganui officer in charge is Community Constable Keith Butters, and he will continue to work with the former outlets.
Mr Baskett had also not heard of any illegal sale or supply of the substances in the district, though police were mindful that could happen.
"We monitor social media and will be following up where there are positive lines of inquiry."
He said police would continue to work with their partner agencies to make sure everyone continued to comply with the new sale and supply laws.
Asked if officers would have a more relaxed attitude to people found using or possessing the substances in the next few weeks, given that some may be addicted, Mr Baskett said officers always had individual discretion in the way they dealt with things.
The Psycho Active Substances Amendment Act removed all psychoactive products from the New Zealand market and also banned testing them on animals.
The amendment cancelled all licences to sell the products, either wholesale or retail, and made it illegal to possess and supply them.