Senior Sergeant Jymahl Glassey said several incidents involving fake $50 notes have also occurred at The Warehouse and Pak'nSave in Petone.
Witnesses described the man presenting the fake money in Petone as a tall Maori man of solid build in his 30s, with facial hair.
It was likely the fake notes were coming from the same source and shopkeepers should be careful when taking cash, Mr Glassey said.
Police recommend shopkeepers consider refusing the note, record the description of the person offering it, and record the number plate and description of any vehicles used by the person.
If possible, call police while the person is still in or near the shop.
Police advised retailers should also consider their own safety first when dealing with anyone offering counterfeit notes.
For information to help identify counterfeit notes, go to the Reserve Bank of New Zealand website and look under "notes and coins" where there is information on how to spot a counterfeit (www.rbnz.govt.nz).