Emmett Raymond Sheard on Tuesday pleaded not guilty to murdering 33-year-old Black at Parklea Correctional Centre in April 2020 and faced the first day of a trial in NSW Supreme Court.

Sheard is accused of using a shiv to stab Black eight times in a frenzied attacked while the pair were in a packed holding cell waiting to appear in court.

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The stabbing occurred after Black and Sheard had about five minutes earlier been involved in a fist fight over buprenorphine, an opiate replacement drug, the jury heard on Tuesday.

After the initial fight, both Black and Sheard argued and flashed jail-made weapons before other prisoners told them to put the shivs away.

A short time later Sheard is accused of attacking Black at the back of the cell and began repeatedly stabbing him in the chest, stomach, arms and legs.

The fatal wound was a puncture to the right lung, the jury heard.

Black ran to the front of the cell and was "cowering" as Sheard slashed him to the thigh, causing him to bleed profusely.

When correctional officers arrived, one armed with a hand-held camera, Sheard could be heard yelling "triumphantly" at Black, saying: "I hope you die you little maggot. I'll f---ing murder you."

The cell was covered by a CCTV camera, but an inmate had covered it with wet toilet paper and the fatal confrontation was not recorded.

During his opening address, public defender Tony Evers, for Sheard, said Black was "desperate" for drugs and attacked Sheard by kneeing him in the head and repeatedly punching him.

He said Black then pulled out his shiv first and swung it at Sheard, who fought back.

Two other men, Luke Anthony Welford and Matthew Ronald Benniss, have pleaded not guilty to being an accessory after the fact to the stabbing and deny they helped Sheard by switching shoes with him and disposing of the shiv.

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