Nokia’s chief technology officer has taken an indefinite leave of absence amid rumors that he disagreed with CEO Stephen Elop about the company’s smartphone strategy.

In an email, a Nokia spokeswoman said CTO Richard Green had taken leave to attend to an unspecified personal matter. The company has not given a date for his return.

Henry Tirri, who heads Nokia’s research division, will take over Green’s post during his absence.

Nokia said Green’s departure “has no impact on our product strategy or our expected product launch timelines.” The company plans to release its first Windows Phone 7 smartphones in the fourth quarter of this year.

Finnish newspaper Helsingin Sanomat reports that Green and Elop disagreed over the company’s change in smartphone strategy.

Elop decided to ditch the company’s Symbian platform in favor of Microsoft’s Windows Phone 7 and abandoned efforts to develop its MeeGo smartphone platform, which it was working on with Intel. Green wanted to continue developing MeeGo, according to information obtained by Helsingin Sanomat.

Elop said at Qualcomm’s Uplinq conference last week that he decided to stop Nokia’s work on MeeGo because it would have taken years to get smartphones to market running the operating system, putting the company further behind its faster moving competitors.

Green joined Nokia in 2010 after a 19-year career at Sun Microsystems, where he expanded Java across computer and mobile platforms in his work on Sun’s software business.