"The schools are so close. And our young people are so precious. We don't want to expose them to any higher risks than we need to.
"I agree that people need the chance to have their lives put back together and to repair the damage within their own lives - without putting at risk other people if we can."
Act MP for Epsom David Seymour said Epsom Girls Grammar was also not told about O'Reilly's placement.
"Obviously they weren't too happy about it," he said.
He wasn't necessarily against sex offenders being placed near schools, but he said that relevant people in the community should at least be notified. "I have great faith in the Salvation Army. And we are not unreasonable people - [offenders] have to go somewhere. But Corrections needs to let people know."
Since September 2016, the Corrections Department has had a policy of notifying communities about the placement of high risk child sex offenders - unless there was a specific reason not to.
Operations director Lynette Cave said that in this case, the schools were not told because it was an emergency placement, it was intended to be short-term, and because there were strict measures in place to monitor O'Reilly's behaviour.
O'Reilly was jailed in 2005 for an indecent assault on a 12 year-old and after completing his sentence he was placed in the shelter on Margot St. He was on an extended supervision order at the time, which is used to monitor offenders who are considered at high risk of reoffending after their release.
Cave said the lodge, which is mostly focused on drug and alcohol rehabilitation, has now been deemed unsuitable for housing child sex offenders and there is no longer anyone with these convictions living there.
The decision to place O'Reilly at the shelter was made by local Corrections staff. Cave said the department had changed its policy to require a district manager to approve a placement of anyone who was subject to an extended supervision order - though this was not as a direct result of the Epsom case.
O'Reilly left the house in May last year after being convicted of breaching the conditions of his supervision order.
He had left the address and got a job without notifying authorities.
The conditions of his supervision order meant he could not associate with people under the age of 16, could not get a job without consent, and could not stay away from the Epsom address overnight.
In all, there are 225 people around the country subject to extended supervision orders.
