Wide-ranging restraining orders will soon be in use to keep suspected child abusers away from children for up to 10 years.
Some will be prevented from going to parks or public swimming pools.
The new Child Harm Prevention Orders against people considered to be a risk to children will be among several changes Social Development Minister Paula Bennett is to announce today as part of the Government's response to its white paper on vulnerable children.
High Court and District Court judges will be able to impose the new civil orders on people who are tried for serious offences against children such as incest, sexual grooming or sexual violation - even if they are not convicted of the offence.
Ms Bennett said the scope of such orders would depend on the circumstances, and could prevent the person from living or working with children, up to blocking any association with children whatsoever, such as sitting next to a child on the bus.
"If it is serious enough, it could be that they cannot hang around parks, pools and other places children gather," she said.
"What we are trying to do is keep these adults away from kids. These people seek children out and try and work in environ-ments where they can be around children, or in many cases, they end up living with a vulnerable woman and her children."
If the order is breached, the person will face up to three years in prison.
She said many cases in which children were killed or suffered serious abuse involved a man who was not a child's biological father.
"This is most definitely pointed at them."
Ms Bennett said the details of the reforms to be announced today had prompted vigorous debate in Cabinet before they were agreed on.
Prime Minister John Key said the changes were the result of a two-year process and would be "significant and bold".
Today's announcements are also expected to include details of power for judges to impose sentences on child abusers, and stronger vetting of staff and workers who are working around children, such as at schools.
Ms Bennett has already ruled out a move to mandatory reporting of child abuse, opting instead to increase awareness of the signs of child abuse and train frontline public and private sector staff on recognising the signs of neglect and abuse.
Child Harm Prevention Orders
*Can apply to people convicted or suspected of serious sexual or violent offences against children.
*District Court and High Court judges can place the order for up to 10 years.
*Can prevent someone living, working or associating with children.
*Up to three years in prison if breached.
*Names are placed on a register for police to monitor.
*Subjects will be unable to legally change their name so they cannot avoid detection.