The teenager shown in a Four Corners program strapped to a chair with a hood over his head while in youth custody in the Northern Territory is suing a former guard at Don Dale detention centre.

Dylan Voller had already lodged writs to start a civil law suit against the Northern Territory Government and this week his lawyers submitted more paperwork, adding Benjamin Kelleher as a defendant.

The ABC has previously reported Mr Kelleher worked in youth detention centres between 2011 and 2014.

The paperwork released by the Master of the Northern Territory Supreme Court to the ABC gives no information about why Voller is suing Mr Kelleher.

In a statement of claim previously filed in support of his case against the NT Government, Voller is seeking damages for being tear gassed as well as being held in the Behaviour Management Unit (BMU) at Don Dale - where the gassing took place - for extended periods of time.

Mr Kelleher has previously told the ABC he was aware of three occasions Voller had been strapped to a restraint chair before the footage shown on Four Corners was filmed.

Five other former Don Dale inmates have also launched legal action against the NT Government.

They include Jake Roper, the teenager who escaped from his cell in the BMU, to which guards responded with tear gas.

The other boys' names have been suppressed by the NT Supreme Court.

Two of them had counterclaims lodged against them by the NT Government, which is seeking compensation for damage to detention facilities during several breakout attempts.

NT Chief Minister Adam Giles announced those counterclaims would be dropped, just hours after the ABC first reported on them.

However, no paperwork has so far been submitted by the Government to stop the counterclaims.

Mr Giles, who took over the corrections portfolio the day after the Four Corners episode aired, also said his government would not offer an out of court settlement.

"I don't believe taxpayer money should be going towards windfall payouts to prisoners," he said in July.