More than 100 offenders were taken off a child sex offender register after a bungle that has forced the Government to amend the law under urgency.
Parliament voted strongly in favour of legislation in September last year to establish a new child sex offender register, which went live on October 14.
However, it since became clear that the legislation was flawed - its wording meant not all child sex offenders had to register, as was intended.
The Government has today introduced an amendment under urgency to fix that mistake.
Police Minister Paula Bennett said since the register came into force concerns were raised that it may not provide for the registration of some child sex offenders as intended.
"There are 107 offenders who have been taken off the register who were intended to be on it," Bennett said.
"The 107 offenders have been monitored by Police and Corrections during the time they were taken off the register but there are certain additional conditions that they will now be subject to as a result of being placed back on the register.
"It is important we pass this bill today under urgency to ensure these offenders are subject to reporting obligations, as per the register, as soon as possible."
Bennett said example of release conditions included to attend counselling, and not being alone with a child under 16-years-old.
"This bill will ensure that a technical issue does not place children at risk from a number of unregistered child sex offenders who were always intended to be subject to registration.
"It is the up-to-date personal information regularly reported by registered offenders that enables police and Corrections to proactively assess and manage the risk presented to children by child sex offenders living in the community."
Bennett said the legislation needed to be clear that offenders who were convicted before the law came into effect but not sentenced needed to register, as well as those sentenced before and on release conditions when the legislation came into effect.
Labour supported the amendment. The party's police spokesman Stuart Nash said a serious mistake had been made.
"The minister said that no sex offender has been convicted of any offence due to confusion in the original bill, that does not mean...that no harm has been done.
"We are all very hopeful that no harm has been done, but we can't prove that. As we know, a conviction does not mean that something has not gone on that we are not privy to at some point in time."
The register requires offenders to provide personal information annually or within 72 hours of a change, such as a new address.
It was intended to apply to anyone older than 18 who has served jail time for a child sex offence, or for non-custodial sentences when a judge orders it.
Parliament voted strongly in favour of the law change in September last year, with only the Green Party opposing because of concerns the costly register was likely to displace funding for proven, less expensive rehabilitation measures.
People remain on the register for eight years, 15 years, or for life depending on their level of offending.