One of NSW's most dangerous criminals Bassam Hamzy has been caught with a mobile phone within the state's highest security jail for the second time in two weeks.

Hamzy, an extremely high-risk inmate who founded the notorious street gang Brothers 4 Life while in prison, was caught with the phone in his cell at Goulburn SuperMax on Thursday night.

Hamzy attempted to flush the mobile phone down his cell toilet. Credit:Corrective Services NSW

The discovery of another phone in SuperMax has raised questions about how contraband continues to make its way into NSW prisons and has led Corrective Services to announce the introduction of mobile phone jamming at the high-security facility.

It is understood Hamzy was using the phone when corrective services officers raided his cell on Thursday night. He tried to flush the phone down the toilet but the officers had cut the water to his cell in anticipation of this.