Microsoft allegedly tracks the location of its mobile customers even after users request that tracking software be turned off, according to a new lawsuit.

The proposed class action, filed in a Seattle federal court on Wednesday in the US, says Microsoft intentionally designed camera software on the Windows Phone 7 operating system to ignore customer requests that they not be tracked.

A Microsoft representative could not immediately be reached for comment.

The lawsuit comes after concerns surfaced earlier this year that Apple's iPhones collected location data and stored it for up to a year, even when location software was supposedly turned off. Apple issued a patch to fix the problem.

However, the revelation prompted renewed scrutiny of the nexus between location and privacy. At a hearing in May, US lawmakers accused the tech industry of exploiting location data for marketing purposes - a potentially multibillion-dollar industry - without getting proper consent from millions.