A Sydney prison has been searched and mobile phones seized after an inmate and Brothers 4 Life gang associate posted on Instagram, boasting of lax security.

NSW Corrective Services searched the privately run Parklea Correctional Centre in Sydney's north-west this morning, seizing a number of mobile phones.

Photos posted to an Instagram account by a Parklea prisoner, who is a cousin of one of the founders of the Brothers 4 Life gang, were published in today's Daily Telegraph newspaper.

They showed the kitchen, prayer area, and even a guard working at a computer in the prison, which is run by the GEO Group.

The Instagram photos were accompanied by comments boasting of the lax security at the complex, including claims prison guards were acting as accomplices, smuggling in tobacco, phones, and drugs such as Xanax.

The Corrective Services Assistant Commissioner for Security and Intelligence Mark Wilson said it was extremely difficult to monitor social media accounts to track the perpetrators.

"Our intelligence people are actively looking at social media aspects, but obviously there's 12,000 inmates in the system," Mr Wilson said.

"They can have those accounts under other names, or other people can use them.

"You can put an inmate's name in and get 150 hits, and none of them are that inmate, so it's very very difficult to track."

But NSW Opposition Leader Luke Foley said there was a pattern of security failures across the state's prisons and Corrective Services Minister David Elliott had failed to keep his promise to clean up the prisons.

"The problem is not so much one incident, it's the pattern of incidents now," Mr Foley said.

"We see it across a number of different prisons - escapes from custody, the entry of banned goods into the prison ... this flies in the face of the Minister's over-the-top rhetoric upon assuming the position, that he personally was going to crack down."

Mr Foley was referring to several prison escapes in the past month, including one at Goulburn jail where a prisoner used a mobile phone to organise a getaway car.

Another prisoner escaped on the same day from custody at the Downing Centre Local Court the middle of Sydney's CBD.

Jamming technology being rolled out: Assistant Commissioner

Goulburn prison also made headlines recently after a maximum security prisoner escaped by climbing a jail wall using bed sheets.

Assistant Commissioner Wilson said the best way to deal with illegal phones in prison was to use "jamming" technology, which blocks the cellular network.

Mr Wilson said the technology was the only way to ensure that prisoners were unable to communicate illegally with the outside world.

He said the technology was already in place at Lithgow Correctional Centre and would be extended for another three years and rolled out at another prison next year, most likely Goulburn.

He said full-body scanners will be introduced by the end of this year.

"It's a challenge that's faced by every correctional jurisdiction in the world, not just New South Wales," Mr Wilson said.

"So that's why we're deploying the latest technology into each maximum security centre by the close of this year."

Mr Wilson said the claims made on the Instagram account about guards being complicit in smuggling contraband were being investigated.