Publicans are warned to look out for foreign coins fed into poker machines after the ruse was discovered in Auckland.
The Department of Internal Affairs is asking poker-machine operators to retain CCTV footage if they find a large number of foreign coins in their machines.
A spokesman confirmed the reported cases were all in Auckland, but declined to reveal which foreign coin had caused the problem.
Internal Affairs has asked manufacturers of the machines to re-test their coin-receiving devices with the foreign coin in question.
