The break-ins were discovered when the stores opened on Saturday morning.
It's understood police have obtained statements from business owners as part of their preliminary investigations and will continue inquiries today.
Northland Chamber of Commerce chief executive Tony Collins was not aware of the latest spate of burglaries but expressed disappointment.
"It's something that puts more pressure on businesses during such hard times," he said.
The Warehouse Stationery was burgled twice on December 8, 2011 and more than $4800 worth of items stolen.
Leonard Henare, was jailed for four-and-a-half years for that and other burglaries in Whangarei.