HELSINKI (Reuters) - Nokia struck back at Google on Friday over its accusation that the cellphone maker was colluding with Microsoft to make money out of their patents.

"Though we have not yet seen the complaint, Google's suggestion that Nokia and Microsoft are colluding on intellectual property rights is wrong," Nokia spokesman Mark Durrant said on Friday.

"Both companies have their own intellectual property rights portfolios and strategies and operate independently."

He also said that some Android devices had "significant (intellectual property) infringement issues" relating to Nokia's patents.

Google, in a formal complaint to the European Commission, said Microsoft and Nokia had transferred 1,200 patents to MOSAID, a so-called "patent troll" which makes money by taking legal action over patent infringements.

Nokia and Microsoft cooperate on smartphones that compete with Google's Android devices. The Finnish phone maker shifted from its own Symbian software in favor of Microsoft Windows in February 2011.

Google's accusations highlight current cut-throat competition in the mobile phone business where companies, including Nokia, are fighting to assert intellectual property rights over wireless technologies.

Nokia's patents have become valuable and stable assets for the company, particularly at a time when falling handset sales and a loss of market share threaten its future.

Nokia has already sued Android device makers HTC and ViewSonic for infringing its patents and is expected to go after others.

Nokia already earns 500 million euros ($618.22 million) a year from its patent royalties in key areas of mobile telephony and some analysts have said a more determined application of its patent rights could boost its income by hundreds more millions of euros a year.

Microsoft said earlier that Google's complaint about antitrust in the smartphone industry was a "desperate tactic" from a company that controls more than 95 percent of mobile search and advertising.

(Reporting by Tarmo Virki. Editing by Jane Merriman)