Thirty-six shops nationwide could face fines of up to $1000 for opening during Easter weekend.
Stores are not allowed to open on Good Friday and Easter Sunday unless they meet exemption criteria, with owners or occupiers who breach trading laws facing prosecution.
The Department of Labour said officials visited 64 shops on Friday and Monday. Forty one were open, five on both days.
That compared with 39 last year and 38 in 2010.
Auckland had the highest number of illegally open shops, 11 on Good Friday and 10 on Easter Sunday.
