Thor Kristiansen, 28, pleaded guilty to conspiring to traffic drugs after police smashed the syndicate that smuggled methylamphetamine and mobile phones into the Alexander Maconochie Centre.

Kristiansen and the late career criminal Anthony John Hagen - who were in jail at the time - were supplied with contraband by a network of smugglers and couriers as masterminds of the drug supply racket between June 2013 and May 2014.

Their co-offenders Ryan Malec, 27, Bianca Rasic, 25, and Menka Krsteska, 24, also eventually pleaded guilty to conspiracy to traffic methylamphetamine.

Police seized almost $85,000 cash and about 830 grams of drugs after surveillance and raids helped smash the operation, which had links to a network of convicted criminals, gang members and a Sydney-based Chinese drug cook.

Kristiansen initially pleaded not guilty in the Magistrates Court to charges of drug trafficking, conspiracy, drug possession, participating in a criminal group, having a phone in jail, and money laundering.

He was committed to stand trial in the higher court but later pleaded guilty to the conspiracy charge.

Prosecutor Mark Fernandez said in court on Tuesday that Kristiansen had played a significant role in the syndicate and his co-offenders were "second or third tier runners, doing the defendant's bidding whilst he was in the AMC".

"He was clearly, in the Crown's submission, the kingpin of the conspiracy."

Justice Richard Refshauge granted Kristiansen bail in 2015, despite resistance from prosecutors, after he expressed regret for his behaviour and said he wanted to take part in an intensive rehabilitation program to help him avoid drugs and crime.

In his decision, the judge noted Kristiansen's "absolutely shocking" record and warned him if he stepped "one toe over the line" he would be back behind bars.

"Do not waste the opportunity I have given you," he said.

"I hope that you will not destroy the trust that I have put in you on this occasion."

Justice John Burns, in his sentencing remarks, told the offender while he suspected he wouldn't have made the same decision to release him, Kristiansen had repaid the faith Justice Refshauge had shown in him.

The court heard Kristiansen, whose troubled childhood led him to use alcohol and drugs from an early age, had spent the past 18 months in residential rehabilitation with significant restrictions on his liberty.

"He has taken real steps, tangible steps, to dealing with his substance abuse which really seems to be the root cause of his offending," Justice Burns said.

The judge said while the fact the crimes took place while the men were behind bars meant the offence was "a particularly serious one", the community's interests were best served by encouraging Kristiansen to continue with his rehabilitation.

Justice Burns sentenced Kristiansen to four years' imprisonment, to be served in the community as an intensive corrections order focused on his substance use, attitudes and employment.

He warned Kristiansen he would be sent back to jail, likely for a significant amount of time, if he committed any further offences.

But he admitted he'd been impressed by the effort he'd made to tackling his drug and alcohol problems.

"You've proved me wrong in that I did not think you were capable of making this achievement," he said.

Hagen had liver cancer and died, aged 56, in 2015. The court had granted Kristiansen permission to visit his bedside days before his death.

Malec was sentenced last year to three years and four months imprisonment and also handed an intensive corrections order for his role in the operation.

Rasic was given a suspended jail term of two years and one month upon entering a good behaviour order.

Krsteska awaits sentencing.