95% of businesses complied with the workplace smoking ban last year, according to figures released to coincide with the third anniversary of the legislation's introduction.
Over 32,000 inspections were carried out by Environmental Health Officers last year.
35 cases were brought, most against licensed premises, but three involved taxi drivers and one a bus driver. 34 were successfully prosecuted.
The Office of Tobacco Control said it is now focussing on tackling the issue of children and smoking.