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."
Mr Key gets rid of his phone every few months incase it has been tampered with or hacked.
"I don't worry about it a hell of a lot, we have pretty good security...I would never go overseas and not have it [my handset] on me.
"And if I left it in a hotel room by mistake, which I have done on a few occasions, I would just throw it out [after getting it back]."
Phone security of world leaders made headlines in 2013, after documents released by whistleblower Edward Snowden showed that the US National Security Agency had monitored the phone conversations of 35 leaders.
Mr Key changed his mobile phone number last year during fallout from the Dirty Politics saga, when a cache of documents released by the @whaledump Twitter account showed the last three digits of his cellphone number.
Mr Key also said he deleted his text messages for security reasons, amid controversy over his correspondence with blogger Cameron Slater.
An investigation by chief archivist Marilyn Little as to whether that amounts to destruction of public records is progressing.
Ms Little agreed to a request from Green co-leader James Shaw to review recordkeeping practices for Mr Key's texts between when he first took office in 2008 and November last year.