Researchers have found only about 30 percent of schools have smokefree signs at their entrances, despite a law requiring them to display them.
The Otago University study showed just 16 of the 50 schools surveyed had smokefree signs at the main school entrance.
The head researcher Nick Wilson said it was disappointing that a considerable proportion of schools did not have the signs up, and tobacco control workers should remind schools of their legal obligations.
He said a 2004 law requires all preschools, primary schools, and secondary schools, to display smokefree signs at their entrances.
The researchers conducted the study using Google Street View.