When most people find their missing phone, it’s followed by a vow not to lose it again.

Prime Minister John Key, on the other hand, quickly bins his.

Mr Key has revealed that he gets rid of his mobile phone every few months for security reasons.

Those precautions are prudent not paranoid, an expert in technology and security says, as phones can be successfully tampered with in only a few moments.

The Prime Minister’s admission follows revelations that other world leaders had their phones accessed, and that US President Barack Obama and others use strict security measures.

While Mr Key’s phone has special security measures on it, he does not assume his conversations are private.

“I kind of work on the principle that I will be [listened to] at some point,” Mr Key said on More FM yesterday.

“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.”

Left behind or not, the phone will be replaced every few months.

“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],” Mr Key said.

Barry Brailey, chairman of the NZ Internet Task Force, a non-profit organisation that aims to improve the country’s cyber security, said that was prudent.

“There is commercially available spyware-type stuff for handsets. If you can get physical access to the handset you can probably install that in less than three minutes.”

-NZ Herald