Police said the 20 kroner bills are much easier to recognize than the forged euros. The fake kroners are smoother to the touch and do not have the metal strip visible when held up to light, TT news agency said Friday.
Detective C.G. Wrangel said those fakes are likely the work of a local forger.
The fake euros, on the other hand, are likely the handiwork of international forgery experts who draft the bills in bulk and spread them around the Eurozone to avoid detection.
Fake euros of all denominations have been detected, officials said.
"I think we're just seeing the tip of the iceberg," Wrangel said.