Police were notified soon afterwards and visited his address to look for McGreevy.
Sensible Sentencing Trust spokesman Garth McVicar said he was outraged that a dangerous sex offender was in a position that enabled him to cut off his electronic bracelet and abscond so easily.
"It is absolutely ludicrous that a criminal like Patrick McGreevy with convictions for sexual offending against children and multiple other convictions was even in a position to be able to escape," he said.
McVicar said: "Anyone who has been convicted of sexual abuse of a child has shown what evil predators they are and should never be granted any leniency or opportunity to put another child at risk."
"Once again the burden falls on the police to find him and I note they are calling on the public for help in locating him."
McGreevy was on a list of 160 "highest risk" electronically monitored prisoners and offenders who are strictly managed in a bid to improve public safety after a spate of breaches.
A special team at the Department of Corrections are notified as soon as a tamper alert is received for anyone on the highest risk list - and action will be taken immediately.
In the past the security company that received the tamper alert would send a "field officer" to check the address before police or Corrections were notified.
The changes were sparked by child sex offender and kidnapper Daniel Livingstone, who allegedly cut off his monitoring bracelet and went on the run in Lower Hutt on August 6, police said. A tamper alert was received by private security company 3M but police did not enter the house for seven hours.
Livingstone was deemed a high-risk offender and was subject to an Electronic Supervision Order that dictated he must wear a GPS-tracking ankle bracelet at all times.
Today is not the first time McGreevy has absconded.
In 2008 the Herald reported that he ran away from his minder after slipping out of an electronic monitoring bracelet.
Six weeks before that he absconded as the courts considered a Corrections Department application for an extended supervision order.
He was quickly apprehended and the courts imposed the order with conditions including McGreevy not associate with anyone under 16, that he be subject to electronic monitoring, and that he have a minder during certain times.
MCGREEVY - A HISTORY OF ABSCONDING:
In 2011 McGreevy was sentenced to a 10-year extended supervision order. Such orders are imposed on high risk offenders after their release from jail so that they continue to be closely monitored.
In May 2008 McGreevy absconded when the Department of Corrections was applying for the order.
He fled for second time in June that year from a secure in Christchurch. The terms of McGreevy's order required him to be under a 24-hour -a-day watch.
In 2011 he breached the order again and was sentenced in the Rangiora District Court.
At sentencing his lawyer Phillip Allan said the breach had been a "spur of the moment decision".
McGreevy now wanted to engage in courses to occupy his time and better himself, Court News reported.
"The pressure of containment builds up and it is almost a compulsion to get away by himself," Mr Allan said.
Judge Gary MacAskill noted McGreevy's list of previous breaches, and sent McGreevy to prison for a six month stint.