Scammers are calling people saying they have warrants out for their arrest and then demanding money, police say.
In a post on its Facebook page, Waikato police told people to be aware of the scam.
"Please be aware of a scam going around at the moment where people are receiving letters and then phone calls saying that they have warrants for their arrest for not paying tax and then demanding money. They can be quite forceful in their demands.
"If you, or someone you know, receives such a letter or phone call and you are unsure, call the IRD to query it with them.
"Whatever you do, do not pay money into someone's account without first checking with IRD."
Police say the scams are usually committed by organised overseas syndicates.
"If you recognise it as a scam and call them out on it they will normally leave you alone."