Rehabilitation workers are welcoming the banning of synthetic highs, but say it won't be the end of the drugs.
MPs last night voted 119 to one in favour of the Psychoactive Substances Bill, meaning drug manufacturers will now have to prove their products are safe before they can be sold.
The law change also imposes restrictions on where synthetic drugs can be sold and requires they can only be sold to people 18 or older.
Wellington's Te Menenga Pai Trust manager Carole Maraku says while she is pleased the Bill's gone through, there will inevitably be a black market for the drugs.
"Someone out there who knows they can make a dollar on this and doesn't actually care about the impact of what that drug does to somebody, they are going to look at ways of being able to sell them."