The virus infected a phone in the world's mobile capital in the last week.
Commwarrior has now been spotted in six countries, including Oman, Italy and the Philippines.
The Finnish sighting was confirmed after researchers at antivirus company F-Secure tested the phone in a secure radio-shielded laboratory.
"We invited the user who reported the case to visit us in the F-Secure AV lab with the infected phone," said Jarno Niemela, a virus researcher writing on the company's weblog. "Then in the radio shielded lab, we investigated the phone and found that it was infected with Commwarrior.B variant, a very close variant to the Commwarrior.A."
Commwarrior operates on Symbian Series 60 devices and can spread from both Bluetooth and MMS messages. When infected a phone will automatically search for other Bluetooth phones and attempt to send them an infected .SIS file.
F-Secure also reports that mobile phone networks are attempting to configure MMS gateways so that Commwarrior messages cannot travel along their networks.
Earlier this month SC reported test on a Toyota Prius had proved current mobile phone viruses are not capable of spreading to car navigation systems as had been suggested earlier this year.