He said alternative protest sites suggested by the council, such as Albert Park and Victoria Park, were also grassed areas and if the protest group moved there then it would only damage more grass.
Mr Mansfield said the protesters were not seeking to claim Aotea Square for themselves and were willing to share the area with other members of the public.
"Given it is a public space, it is good to see it being used."
He said the council could not put forward any evidence about the numbers of people who would normally use the space.
"If Your Honour does as the council asks, the council can control when, where and how and the duration for which people can speak."
Mr Mansfield received a round of applause from the packed public gallery of Occupy Auckland members as he took his seat in court.
Council lawyer Ross Burns said it was important for people exercising their rights to respect the rights of others.
He said the matter was not about political opinions but how they chose to express them.
"It's there for all to use, not just a few."
He said the patch of grass was "where kids can play and not worry about falling over and hurting themselves on the hard stones and paving area."
Veteran protestor Penny Bright told the court that the occupy Auckland group was one of 2600 groups protesting around the world.
She said there was nothing new in using camping as a form of protest.
"A few squares of brown grass being wasted to get rid of us, does not cut the mustard, Your Honour."
Ms Bright also accused some councillors of letting their political views influence their decision to take legal action against the protestors.
It is understood that if the court grants the injunction, the council will give protesters a few days before they are moved on.
Judge David Wilson has reserved his decision.
