"One of the most serious cases involved a man who was jailed for sending a disturbing video to a woman over Facebook," Justice Minister Amy Adams said today in a speech launching a new agency to help victims of online abuse and bullying.
"We've also seen prison sentences imposed on a man for sending half-naked photos of his ex-girlfriend to a shared work email address.
"That tells me the law is working to weed out and punish the worst offenders. And it's protecting victims."
The minister pointed to the prosecutions as evidence the controversial measures were worthwhile.
"During the passage of the legislation, I received criticism that it was simultaneously going too far and at the same time wasn't needed.
"Everything I've seen since confirms the Government's view that this legislation and the tools it creates are absolutely justified."
The Harmful Digital Communications Bill passed in June last year. Designed to crackdown on cyber-bullying, it progressed after the so-called Roast Busters case, in which teenage boys boasted online about sex with drunk and under-age girls.
A new offence was created of sending messages or posting material online that was intended to cause harm, and did so.
Another new offence is incitement to commit suicide in situations where the person does not then attempt to take their own life.
Ms Adams said today that, as of last month, 89 criminal charges have been laid under the new legislation.
Those prosecutions had led to seven jail terms ranging from 90 days to 11 months, three home detentions, five community work sentences, one community detention and one supervision.
The Harmful Digital Communications Bill will also set up an "approved agency" that will chase up internet service providers or companies such as Facebook or Google to remove a harmful communication.
That agency will be NetSafe, which from November 21 will have responsibility for receiving, assessing and investigating complaints.
"The free service is available to all people in New Zealand who experience online harassment or cyber-bullying," Ms Adams said.
"The creation of this role sets a new benchmark for curbing online harassment and intimidation. I'm told they expect to deal with up to approximately 1500 complaints. For most cases, NetSafe will seek to have harmful content removed within a couple of days."
New court orders will also provide a new civil process for dealing with serious or repeated harmful digital communications.
During the legislation's third and final reading last year, Act Party leader David Seymour said the Bill was a "knee-jerk" reaction that was a "case study in bad law making", and would have a chilling effect on free speech.
He said principles in the legislation, including that sensitive personal facts should not be disclosed and communications should not be indecent, were "appropriate if we were about to embark on a school camp", but should not be written into law.
"It says that you cannot offend somebody. So, for instance, would the Flight of the Conchords' song Albie the Racist Dragon be offensive if it was communicated online?" Mr Seymour asked at the time.
Loopholes could be closed by amending existing laws, he said, including extending the intimate covert filming provisions in the Crimes Act to cover "revenge porn".
The Green Party chose to allow the rare step of a split vote, with Gareth Hughes, Russel Norman, Julie Anne Genter and Steffan Browning opposing the law.
