The Warehouse has copped a $19,800 fine for sending marketing emails to people who have tried to unsubscribe.
The Department of Internal Affairs said the fine was the largest issued to date.
The Warehouse had been formally warned about their email practice in January 2011, Internal Affairs' manager of email compliance Toni Demetriou said.
More complaints made this year had sparked a separate investigation and found The Warehouse had broken the law 132 times where people had tried to unsubscribe to the retailers emails and still received them.
"Obtaining the recipient's consent as well as acting on unsubscribe requests from recipients are critical elements of the Unsolicited Electronic Messages Act 2007," Demetriou said.
"If a recipient uses an unsubscribe facility within a commercial electronic message then the recipient has withdrawn their consent to receive future marketing messages."
Demetriou said companies and organisations need to comply with the legislation and have robust policies, procedures and operating practices around their Email and SMS marketing practices.
The Warehouse did not lodge an objection under the Act to the civil infringement notice and paid the $19,800 imposed in full.