The latest software release for Apple’s iPhone may be reducing the battery performance on some devices, according to reports from some users and mobile networks.

The latest update for the iPhone – called iOS 6.1 – is reported to be making certain models contact the mobile network repeatedly, causing the battery to drain in a short period of time.

A large number of users have posted to Apple's online support communities to complain about the issue, with many saying their device is also overheating.

The bug is suspected to related to the iPhone's mail application, with some companies reporting increased pressure on their mail servers due to the constant data requests.

Earlier, a representative of Vodafone UK advised customers who had not upgraded to iOS 6.1 to delay doing so until Apple had responded to the issue.

In a statement posted on the network's online support forum, the spokesman said they were aware of the issue and that Apple was “working on a solution”.

He said the problems caused by the software were intermittent and appeared to mainly affect the iPhone 4S model.

A spokesman for O2 Ireland said they had not yet received any reports of issues with the iPhone software upgrade but the network was monitoring the situation.