"There is very good evidence that particularly those high-risk offenders will be driven underground if they are named and shamed," Ms Tolley said.
Police would be required to develop "very good security" against leaks.
In recent years, there have been high-profile leaks from agencies such as ACC and the Earthquake Commission, revealing private details of thousands of claimants.
Associate Professor Ian Lambie of the University of Auckland School of Psychology, said if the agencies involved were able to ensure the register was kept confidential, and it was used to minimise the risk of reoffending, there would be merit in having it.
He said there would have to be tight controls "to ensure names did not get out into the general public".
Defence lawyer and prison reformer Peter Williams, QC, said he did not think the register would achieve very much.
"I think the police have a certain amount of licence in cases where you have paedophiles near schools.
"I can understand the philosophy or the ethos, and I think it's probably well intended.
"But on the other hand, you've got parole and other ways that people can be watched. I don't think it's necessary to have these things published."
But the Sensible Sentencing Trust has called for the register to be available to the public.
And a spokeswoman for Prevention of Child Abuse, Nadia Crighton, said: "The fact is that naming these offenders will help stop the continuation of abuse, it will stop them reoffending.
"This is about protecting our children. It's about time their rights come before those who want to abuse them."