The Police Investigations and Review Commissioner (PIRC) ruled the use of force was proportionate and justified in disarming a man, 28, who had repeatedly held a knife to his own throat.
The incident took place in the Arden area during the early hours of February 8 this year.
Police arrived on the scene where a man, acting in a violent and drunk manner, was threatening to hurt himself. Officers then used a taser to subdue him. He was unharmed and did not require medical attention.
In his report, Professor John McNeill said: "I am satisfied that the use of the taser was proportionate and justified."