An inmate with more than 100 convictions was taken to North Shore Hospital after allegedly hiding drugs and a mobile phone in his rectum.
Patched Mongrel Mob member Paul Cloke is said to have raised suspicion among prison guards at Auckland Prison, Paremoremo, by acting "bizarrely" in his cell.
He was kept in an observation room before being sent back to his cell in the prison's West Wing with other medium-security inmates. But a prison source said that the next morning guards noticed something was seriously wrong with Cloke.
"He was hallucinating and behaving weirdly," the source said. "He was walking around and falling over - at one point he nearly passed out. Something was majorly wrong."
It is believed drugs concealed in Cloke's rectum had begun to leak into his system.
Cloke was taken to North Shore Hospital where doctors surgically removed the drugs. It is understood that during stomach surgery doctors discovered a cellphone up Cloke's bottom.
The source said prisoners who hid cellphones usually covered them in something plastic, such as bread wrappers. "It wasn't a smart phone, I think the inmates prefer the smaller models," he added.
Another source said: "Cellphones are highly valued behind bars. Women have handbags to carry things - in prison men use their bums like a handbag. That's where they hide sim cards, chargers, all sorts."
Auckland Prison manager Tom Sherlock said he could not comment on the case as charges could be laid against the inmate.
But he said Corrections placed "considerable emphasis on preventing contraband from entering prisons by apprehending those who attempt to smuggle it in".
"These measures all contribute to improving public safety and our ultimate goal of reducing re-offending," he said.
Cloke's mother Rawinia declined to comment, but said she had no idea her son had been hospitalised for four days earlier this month.
Ten years ago, the Herald on Sunday revealed Cloke had 101 convictions. In 2004 he served a jail term at Paremoremo after a 12-day crime spree in which he burgled more than a dozen homes around the North Island.
Three years later he "got his patch", after an attack on a rival gang member and a prison guard.
Cloke was one of four Mongrel mob members who attacked a senior Black Power member at Rimutaka Prison while he was being escorted by a female guard.
In a three minute-attack the man was stabbed seven times with a metal weapon made from a bucket handle.