Some of the new ''cheater's'' apps conceal incriminating calls and texts; others allow them to be kept off the bill. One program causes messages to self-destruct after they are read.

The newest of these is CATE, which stands for Call and Text Eraser. Launched last month by American student Neal Desai, it hides calls and SMSs from selected contacts until a secret code is entered. Should a partner walk in while an illicit message is being typed, a quick shake will erase it.

But beware, CATE, like many of these apps, can be used in reverse.

Partner A can secretly download CATE on to Partner B's phone, for instance, creating an invisible record of calls and texts - even after Partner B has deleted them.

Other apps available to those trying to keep tabs on their partners include one that allows you to secretly ''dial in'' and listen to someone's phone and another that says you can ''see their movements [and] get directions to their location''.

A Victoria police spokeswoman was not able to say how many instances there had been of smartphones being used to ''stalk'' a partner because the police database was not set up to track that specific information.

A spokeswoman for federal Attorney-General Nicola Roxon said the Telecommunications (Interception and Access) Act 1979 ''may apply'' to spyware on smartphones, with penalties of up to two years' imprisonment for unlawful interception. She said the proliferation of smartphones had prompted the Parliamentary Joint Committee on Intelligence and Security to review privacy laws, and that the government would consider ''the creation of a new right to sue where serious invasions of privacy occur''.

Spencer Zifcak, president of Liberty Victoria, told The Sunday Age: ''We don't appear to have any laws that govern invasion of privacy of this kind … the Surveillance Devices Act in Victoria was passed in 1999 so it's way behind technological advances [such as smartphone apps].''

Professor Zifcak also called for the introduction of a statutory right to sue for serious invasions of privacy.

A Victorian government spokesman responded, ''The Surveillance Devices Act 1999 is broad enough to deal with use of new technologies, including smartphones and their applications'', and said hacking, bugging or tracking another's smartphone was a violation of federal criminal law.

The CATE app, which costs $5 and is not visible on a phone's home screen, has been downloaded by 10,000 Android users. Sales are expected to soar when an iPhone version is released next month.

Mr Desai bought CATE from a Florida policeman who created it after his pal, incriminated by saucy texts, suffered a painful divorce. ''He didn't want it to happen to any more of his friends,'' Mr Desai told Newsweek.

While critics have branded the app ''despicable'' and ''immoral'', Mr Desai claims it will ''cut down on squabbles and domestic violence''.

Tech-savvy love rats can also use TigerText, which wipes SMSs after viewing; PrivateSMS, which protects texts with a password; and Fox Private Message, to delete SMSs remotely.

Talkatone allows you to make calls that aren't logged on your bill. And when a conversation is inconvenient you can use SlyDial to fake bad reception, go straight to someone's voicemail and promise to call them later. It works only on US numbers, though Australian iTunes users are requesting a local version.

Sneaking iTrack on to another's mobile allows you to ''follow [them], see their movements, watch the speed they are travelling at, get directions to their location and view a street level picture of any address they have been at'', according to its website.

■mlallo@theage.com.au