Police will now be able to find domestic violence using their mobile phones, even if they're too scared to say where they are.

A $12 million service letting emergency call-takers use GPS signals, has just been launched.

It comes after emergency services last year had to make almost 2000 special requests to phone networks to get information.

Changes to privacy laws earlier this year mean those requests aren't needed anymore.

The technology's already in place and Police Superintendent Dave Trappitt said he's had a number of situations relayed to him where it's been proved successful in land searches, marine searches, and incidents involving family violence.

He said it's also useful in dealing with tourists.

"We get a number of calls from tourists who are on the highways and they don't quite know exactly where they are. What this can do is identify the general area as to where they were."

Minister of Police Paula Bennett's calling it a fantastic development to be able to pinpoint where mobile callers are.

She believes it'll be useful in family violence situations where the perpetrator hangs up calls made to police by victims for help.

"And there's been an actual incident where this has been used in that case," Minister Bennett said. 

Communications Minster Simon Bridges said the service can't be used to track offenders. It can only be used when people call 111 - and data will be deleted within an hour.

 

The move had been signalled last month when the Government signed off on a multi-million dollar indemnity for Google - the creator of the android system emergency location system.

In order to use the system, the Government had to accept Google's terms and conditions - which include an obligation to indemnify.