Parents worried about cyberbullying can now pay to get their child's phone forensically investigated to recover deleted text messages.
However, internet safety watchdog NetSafe said using the commercial service was an "extreme move" that could damage family relationships.
Data recovery company Computer Forensics NZ is offering services that allow concerned parents to access and recover data from their children's phones.
"We can access such offensive texts or messages even when they have been deleted. You can picture it - a young girl receives such a message, she feels hurt, so she immediately deletes it," Computer Forensics managing director Brian Eardley-Wilmot said.
By recovering full conversations, parents could collect evidence to show the school, or even to take for legal advice.
The company could also track the whereabouts of a child through geo-location analysis on the phone.
Mr Eardley-Wilmot said the success of the service would depend on how seriously parents took the issue.
"If parents don't recognise cyberbullying as a problem, they wouldn't try and solve it."
He said the cost would be from about $500 plus GST.
Christchurch-based NZ Forensics' managing director, Mike Chappell, said such requests from parents were not uncommon.
"We get about a dozen calls a month from parents who suspect their children are sexting or other things and want to find out what's going on," he said.
Mr Chappell said he also recovered data from social media apps such as Facebook, Instagram and Snapchat.
"I recover more data from mobile devices than on computers."
He said his company charged about $800 plus GST.
The service has been welcomed by an Auckland mother whose daughter, then 15, fell victim to cyberbullying five years ago.
The woman, who did not want to be named, said if the service was available at the time she would have used it.
"If you have evidence of bullying, it would have forced [the bullying girl's] family to stop it. A tool that stops the bullying has got to be good."
NetSafe executive director Martin Cocker warned this could breach trust between parents and children, damaging relationships.
"If your child is a victim of cyberbullying, there are better ways to go about it than forensically investigating their phone," he said.
"You might want to talk to the management of the school and ask them for assistance, you might talk with the child's friends. Forensically investigating a phone is such an extreme move."
A spokesman said the Office of the Privacy Commissioner had not dealt with any complaints about parents using forensic services, and the Privacy Act did not apply to family affairs unless the subject was "highly offensive".
• The safest way is to not send explicit pictures at all - but if you do, don't make yourself identifiable. For example, hide your face and any tattoos.
• However, if you send multiple photos, even without identifiable features, a recipient can put it together in a composite image.
• Remember that although a photo sent via Snapchat will disappear, it can be captured permanently through various methods, including screenshots and other apps.