Warning: iPhones can spy on you

3G iPhones and iPads are storing tracking data that shows where a user has been. Photo / Supplied

New Zealanders are being warned smartphones, including iPhones and Android handsets, could be secretly tracking their every move - and storing information that others could view.

Apple is coming under increasing pressure to explain its decision following research by security experts in Britain.

The experts found later versions of the iPhone, as well as other 3G-enabled Apple devices, collect location data and timings automatically, saving them in a file on both the handset and on the computer used to manage the device.

The file is also transferred to new devices after they are plugged into that computer. After installing a simple program, versions of which are available online, anyone with access to the hardware can see a detailed map of the owner's movements.

It is unclear whether the feature can be disabled.

Yesterday the Guardian newspaper reported that smartphones running the rival Google Android system collect data in almost exactly the same way as the iPhone, although for a shorter period.

New Zealand Privacy Commissioner Marie Shroff said: "From what we understand, it's not clear why Apple wants the information or if Apple even has access to it. Does Apple have access to it, and if so, for what purposes?" she said.

"We'd also like to know the benefits of collecting the information."

Ms Shroff said the feature on the Apple phones was worrying.

"We are concerned that unlike other location-based features on phones and computers such as GPS and wi-fi, users aren't aware of this new one, which also means they won't be able to block it.

"Knowing how quickly technology develops, it won't be long before someone develops a program to hack into the location information."

Magnus Eriksson, a Swedish programmer, said Android devices also keep a record of the locations of the last 50 mobile masts they have communicated with, and the last 200 wi-fi networks they "see".

It is not yet known whether the lists are sent to Google. Apple devices store the data for up to a year.

In addition, some computer skill is required to extract the data. By contrast, the Apple file is easily extracted directly from the computer or phone.

- Independent, staff reporter