Prime Minister John Key gets rid of his mobile phone every few months for security reasons.
Mr Key has also revealed that he would never take his phone into sensitive meetings - whether it was turned on or not - for fear that it could be turned into a listening device by those seeking to eavesdrop.
The Prime Minister said his phones have special security on them, however he does not think they are impenetrable to espionage.
"I kind of work on the principle that I will be [listened to] at some point. So I have, without being stupid about it, more security on my phone than most people have, but it doesn't mean that you can't break into it," Mr Key said on More FM today.
"If I was having a conversation with my national security advisers ... I would never have a mobile phone in the room I'm in...because you can use it as a listening device, whether it is on or not."