Apple confirmed last night that a glitch in its new iOS5 platform update was causing a “lower than expected” battery life on devices running the OS – and has promised that an update due in a few weeks will fix the issue.

"A small number of customers have reported lower than expected battery life on iOS5 devices,” Apple said in a statement. “We have found a few bugs that are affecting battery life and we will release a software update to address those in a few weeks.”

The move follows reports of customer complaints of battery problems with the new iPhone 4S and older models that have been upgraded to run the new software.

It is not clear what exactly is causing the battery drain though some reports have highlighted a problem with a location services feature that automatically detects the device’s current global timezone. Turning this feature off has reportedly improved battery life for some users.

The Guardian reported on Friday that Apple engineers had begun contacting individual users to try to pin down the causes of the problem.

The same newspaper reports today that Apple has already released the new version of the iOS5 software to the developer community. This version “will undergo wider testing with developers to find any outstanding problems or bugs before it is issued more widely,” The Guardian says.

As well as fixing the battery problem, the update is also thought to include new multitasking gestures for the original iPad, unspecified “security improvements,” improved voice recognition for Australian users and a fix to a bug for iCloud documents.