Internet giant Google said sorry to New Zealanders Tuesday for collecting personal data from wireless networks for its "Street View" mapping service, in the latest in a series of apologies.

The company said it did not realise until earlier this year that cars it was using to photograph public streets were also gathering information known as "payload data" sent over unsecured Wi-Fi systems.

Unencrypted information sent on Wi-Fi systems that are not password-protected potentially contains personal information, including the content of e-mails.

Google said as soon as it realised its error, it garaged the Street View cars and began working with the New Zealand Privacy Commissioner Marie Shroff on ways to address the problem.

"Our collection of payload data was a mistake for which we are sincerely sorry, and we'd like to apologise to all New Zealanders," Google said on its New Zealand blog.

Google announced in May that its Street View cars, taking photographs of cities in more than 30 countries, had inadvertently gathered data sent over unsecured Wi-Fi systems, sparking complaints by data regulators worldwide.

In Britain, Google agreed to delete private emails and passwords, while in Australia it was found to have broken privacy laws but no punishment could be imposed.

The company is being sued in the US, while in Germany it agreed to allow people to opt out of Street View over privacy concerns, in which case their houses would be pixellated.

On its New Zealand blog Google said the company had never used payload data in its products or services but acknowledged there was public concern about its actions.

"Some people felt we should have been more explicit about what we were collecting," it said.

"We also think we should have had greater transparency around our initial collection of publicly broadcast Wi-Fi network information. We're sorry for not realising this sooner."

Shroff welcomed Google's apology but warned its initial actions were "not good enough" when it collected the content of people's communications.

"It is important that Google makes sure that these mistakes do not keep happening," she said in a statement.

"For technology to be successful, people need to trust it. If they don't trust it, they won't use it."

Shroff said Google had committed to improving staff training on privacy issues and checking new products carefully before they were released.

The privacy commissioner referred the matter to police in June and specialist cyber crime officers reported three months later that they did not believe a criminal offence had been committed.

However, they said the case underlined the need for Web users to put in place security measures when using Wi-Fi systems.