A Japanese company has been forced to tone down a smartphone application that allows women to secretly track their husbands or boyfriends.

The 'Boyfriend Log' app allows people to track the movements of a smartphone, and presumably its owner.

The company behind the application, Tokyo firm Manuscript, marketed it towards women as a way for them to keep tabs on their boyfriends or husbands.

It also suggested women secretly install it on their partner's phones.

But after complaints that the app was a form of spyware, its maker has apologised and toned down its functions.

An icon on the targeted smartphone will now be displayed to show the application is running.