A police tribunal has heard that an activist, anti-police lawyer has no credibility when he claims he was arrested illegally during the G20 three years ago.

In closing arguments, defence lawyer Alan Gold accused Nicholas Wright of either exaggerating or lying about what happened.

Wright accuses Const. Ryan Simpson of arresting him and warning him he had no right to remain silent.

But Gold calls the allegations absurd, and says there's doubt about whether there even was an arrest.

Prosecutor Brendan Van Niejenhuis says Wright was honest, but his credibility should have no bearing on the matter.

He says it is irrelevant whether Simpson actually arrested Wright or simply detained him for investigative purposes.