"We want to stop these people falling through the cracks and disappearing into our communities at the end of their sentences," Mrs Tolley said.
"We want to know where they are and have more information about their circumstances, so they can be managed, and increased risks of reoffending can be detected before they take place so that we have the chance to take action.
"Agencies will have access to the register, but it won't be open to the public.
"I believe there needs to be one definitive place with all of the information. Making it public could identify victims, and could drive offenders underground where they can't be managed."
The Sensible Sentencing Trust called for the register to be made public.
Spokeswoman Ruth Money said it was "absolute nonsense" for Mrs Tolley to suggest a public register could drive offenders underground.
"Paedophiles already live and operate underground, often masquerading as a caring parent, religious leader or sports coach. Some paedophiles will go into prison in denial, will stay in denial, and when they come out will remain in denial," Ms Money said.
"The register should be public."
Ms Money said the proposed register was a "weak copy" of only some parts of the United Kingdom's sex offender register. She said that, along with name suppression laws, meant the register would have "no positive public safety effect whatsoever".
"Name suppression enables sex offenders. They don't have this law in the UK and nor should NZ," she said.
Read more: Kneejerk response could increase reoffending
