Mr Gotlieb is seeking to have Nikau's conviction dismissed.
"What happened was a very strong man holding off someone," Mr Gotlieb said. The prosecution's evidence was reliant on the complainant who, he said, was "in an emotional state that day".
Justice Wylie reserved his decision pending his reviewing a police transcript of evidence. He said a decision would likely be made before Christmas.
At Nikau's earlier appearance, in the Huntly District Court, Mr Gotlieb asked for a discharge without conviction, saying the sportsman had done "volumes" for the Huntly community.
But the request was opposed by Nikau's daughter and the lower-court judge, who said there had to be consequences for the actions.
The judge ordered Nikau to pay $250 in reparation in the next 21 days, and $132.89 court costs.
Earlier this year, Nikau told media that he feared for the safety of his grandchildren, aged 6 and 4.
Both children, who are now living with their father in Melbourne, had been in the long-term care of grandparents and extended family until Heaven-Leigh picked them up the week before the incident and refused to hand them back.