Privacy watchdogs are worried about intrusive new "reverse search" websites that allow users to type in a street address and discover who lives there.
The websites have sparked warnings that information on the sites, which can also include phone numbers, could be used to commit crimes, such as stalking, or finding out if someone is home before committing a burglary.
The sites, which the Herald on Sunday has decided not to name, differ from the White Pages, where users have to know someone's name to get their address.
Privacy experts say the reverse search sites would be illegal, except legislation hasn't kept pace with advances in technology.
A Palmerston North resident who discovered his personal information on a reverse search site and fought to have it removed said he was concerned that burglars had already used the information to scope his house.
IT student Nigel Jourdain said he came across the information while Googling his name as part of a university assignment.
"I typed in that and our street and I found a good number of the neighbours' names came up with phone numbers and addresses.
"It got me a bit concerned that if a criminal wanted to target our street they could type in our address and it would come up with our phone number and you could ring up and find out if you were home."
He said he had experienced "hang up phone calls". There had been burglaries in the area and his neighbours had also experienced hang up calls, he said.
"Whether or not that is connected to that, who knows? But it did concern me that someone could target you."
He contacted the site to have his information removed, which became a "bit of a process".
The site is run from Germany by a Belarussian national called Dmitry Shelest, who did not reply to email or phone requests for an interview.
To illustrate how prevalent the information on such sites is, the Herald on Sunday looked up addresses in one New Zealand's priciest residential areas, Auckland's Herne Bay, where the median house price last year was $5.25 million.
Details for four of the 12 properties on the street were easily traceable, upsetting residents.
"I wouldn't like anybody being able to find out anything about me. The family here, they're a well known family here anyway. I don't know that they would like anyone being able to access information about them," said one.
Police use reverse telephone directories to find the origin of an emergency call.
The Telecommunications Privacy Code bans telecommunications companies from allowing "reverse searches" and the Privacy Commission is calling for the code to be updated to ban these types of sites.
Assistant Privacy Commissioner Katrine Evans said: "There are clear privacy and safety concerns with publishing reverse directories. If people find that their information is up there and are unhappy, we encourage them to apply for it to be taken down, and to contact us if they are concerned."
White Pages publishers Yellow communications manager Katherine Cornish said the company is checking whether its database had been hacked to access such information.
"On occasion, third parties have tried to use our data in breach of our copyright. In these circumstances we will vigorously protect our data, including by initiating legal proceedings where appropriate."
Netsafe Martin Cocker said the proliferation of information on the internet meant the data could have come from multiple sources.
"It doesn't feel like consumers are in control of their own information sharing."
Keep your neighbourhood safer from thieves and burglars
Get to know your neighbours and exchange contact details. Let neighbours know when you are going away. Let each other know if visitors or tradespeople will be in your house while you are away. If your neighbours are away, you can help them by making their house look "lived in".
• Turn on lights at night.
• Close curtains at night and open them during the day.
• Mow lawns.
• Clear mail, especially junk mail and newspapers.
• Use their clothesline or driveway.
• Keep an eye on their house and walk around it once a day to check it is secure.
• Question strangers, but don't say the neighbours are away. Write down descriptions and note the time and date. For help writing a description, visit the Neighbourhood Support website for a fact sheet.
• Write down the registration numbers of unfamiliar vehicles moving slowly or stopping in the street.
• If you arrive home and think there's a burglar inside your house:
• Dial 111 and ask for police.
• Don't go inside.
• Go to a safe place and wait for police.
• If you think something is not right, but you are not sure, call 111 and let police decide.
- NZ Police