It is expected adult websites will be given three months to implement and enforce the new rules.
HOW WILL IT WORK?
The porn block will restrict access to many adult sites, including free porn sites such as PornHub, YouPorn and RedTube - which attract close to two billion visits a month worldwide.
Users will need to use an official form of ID such as a driver's licence or passport to access such websites.
Users will initially be shown a non-pornographic landing page, according to AgeID spokesman James Clark.
"When a user first visits a site protected by AgeID, a landing page will appear with a prompt for the user to verify their age before they can access the site," he told The Sun.
"Each website will create their own non-pornographic landing page for this purpose."
After clicking on the site they'll be asked to register with AgeID before being asked to verify their ID through a mobile SMS, credit card, passport or driver's licence.
Once verified, the user will be able to access all porn websites.
If sites fail to implement the new law, they can face fines of up to £250,000 (about NZD$484,000).