The Department of Internal Affairs' (DIA) internet filter is now operational and is being used by internet providers (ISPs) Maxnet and Watchdog.



Thomas Beagle, spokesperson for online freedom lobby Tech Liberty says he's "very disappointed that the filter is now running, it's a sad day for the New Zealand internet".



He told Computerworld the filter went live on February 1 but DIA has delayed announcing that until it held a meeting with its Independent Reference Group. He says he's disappointed the launch was conducted in such a "stealthy mode".



The manager of the Department of Internal Affairs' Censorship Compliance Unit, Steve O'Brien, denies any subterfuge in the launch, saying the trial has been going on for two years and that has been communicated to media for "quite some time".



"The Independent Reference Group has met and the filter system processes were demonstrated as set out in the code of practice, that is that the website filtering system prevents access to known websites containing images of child sexual abuse," says O'Brien.



Beagle says the DIA refuses to say which other ISPs will be joining the filter, claiming the right to negotiate in secret.



However, Tech Liberty understands that Telstra Clear, Telecom and Vodafone have said they will implement the filter, with Orcon, Slingshot and Natcom saying that they won't.



Vodafone spokesman Paul Brislen says Vodafone took part in the filter trial and is awaiting word from the DIA about the next steps. The company will likely use the filter, he says, and when it does customers will be informed.



Orcon CEO Scott Bartlett says it is not true to say Orcon will not be taking part.



"We are still working with officials to fully evaluate this and ensure it doesn't impact on our customers' experience," he says.



O'Brien says there is no compulsion for ISPs to tell their customers their internet service is being filtered.



"It's a voluntary system and there's no legislation," he says, adding he understands the ISPs currently on the system have informed their customers.



David Zanetti, technical spokesperson for Tech Liberty, says he fears the stability of the New Zealand internet will be at risk.



"It is a single point of failure, introduces a new and very tempting target for hackers, and by diverting traffic will cause issues with modern internet applications."



O'Brien, however, says ISPs are being brought on gradually in a staggered way.



Tech Liberty says it is also concerned about the expansion of government powers represented by the filter.



"It establishes the principle that the government can choose to arbitrarily set up a new censorship scheme and choose which material to block, with no reference to existing law," the group claims.



TechLiberty says the list of what is filtered is kept secret, in direct contrast to the rest of New Zealand's censorship regime where the Chief Censor must publish decisions banning offensive material.



O'Brien says the Department is writing to all ISPs advising them that the filter is available to them and they will be brought on gradually.



"We anticipate all major ISPs will embrace this development as they have the many other filters they employ on the internet for a range of purposes.



"The Digital Child Exploitation filter provides them with the means to prevent their customers from accessing these illegal websites, inadvertently or otherwise and will assist in raising awareness of the worldwide problem of child sexual exploitation."



He says trials over two years showed that the filter does not affect the speed or stability of the internet and participating ISPs are happy with the performance of the system.