High-risk inmates charged with terror offences will be banned from speaking Arabic during visits and phone calls in the super-maximum prison unit at NSW's Goulburn jail, it's been reported.

From Sunday, 13 inmates classified as Extreme High Risk Restricted will be forced to speak English when communicating with the outside, News Corp Australia reports.

Letters will also be required to be written in English under the new restrictions at SuperMax.

NSW Attorney-General Brad Hazzard said he ordered the restrictions in response to the nation's heightened terror climate.

During visits, prison officers will stand within earshot of inmates and record their conversations, with the power to eject visitors if Arabic or other languages are spoken.