Twenty-two stores were found flouting the law by trading on Good Friday.
A Department of Labour spokeswoman said they were among 38 shops visited by inspectors today.
She would not comment on their location or what they were selling because they may face prosecution.
Today's figure is consistent with previous Good Fridays, with 22 stores in breach of the law last year and 19 in 2010.
The director of a chain of garden centres said he opened today because a $1000 fine - the maximum for each store open - was no deterrent to breaking the law.
Oderings director Darryn Odering said Good Friday signalled the start of the company's annual sale and had been its busiest day of trading since 1970.
The company had six shops in the North Island and five in Christchurch. It stayed open on Good Friday despite a law change in 1990 that required it to close.
"We were largely ignored for opening until 1998 when we first got prosecuted,'' Mr Odering said.
"Last year we were prosecuted in our North Island stores, but not in Christchurch.''
Mr Odering said he expected fine weather in Christchurch to help make today's revenue a record for Good Friday.
Last year, the Labour Department visited 54 retailers throughout New Zealand on Good Friday and Easter Sunday, and found 39 shops trading illegally.
Most shops should be closed on Christmas Day, Good Friday, Easter Sunday and Anzac Day before 1pm.
Retailers with exemption include dairies and service stations allowed to sell essential items and pharmacies.
Businesses providing a service, such as restaurants and hairdressers, can open but not sell products. Garden centres can only open on Easter Sunday.
The Retailers Association told TVNZ the number of stores opening illegally meant the laws should be revised.
Cornerstone Bar in Tauranga said it had to be careful about opening on Good Friday because it was fined last year for breaching Easter trading laws when it sold alcohol.
Parliament has attempted to change Easter trading regulations 14 times.
In late 2009 a Member's Bill failed by three conscience votes, 62 to 59.
- By Kate Shuttleworth and Abby Gillies of APNZ
