A police spokesperson confirmed their presence and said they were monitoring the situation.
Three people are blockading the entrance to the site with their arms locked inside concrete-filled barrels, while several arborists have occupied the tree-tops, and dozens of others have formed a human chain around the site.
A spokeswoman for the group said they planned to remain at the site today to ensure that the trees remain standing.
Arborist and protester Zane Wedding, who is occupying one of the trees, called on Auckland Mayor Phil Goff to step up.
"This is Auckland, where the city's symbol is the pohutukawa, but the real symbol of this city right now is that pohutukawa lying dead on the ground below me.
"Mayor Phil Goff needs to come down here, step up and take responsibility for these trees, and the central Government must reinstate general tree protection to stop this happening any more anywhere else."
The section of land has recently been on the market, with local residents under the impression any sale would be on the condition the trees would not be removed.
In protest, local residents and environmentalists have been occupying the site, some perched in the trees, for more than 70 days.
Steve Abel, a veteran environmental activist and now Green Party candidate for New Lynn, has been involved since the beginning, calling for Auckland Council to work with the property owner, to step in and acquire the land, either by purchasing it or through a land swap.
The ability to chop down native trees on private land stemmed back to changes under the previous government to the Resource Management Act in 2012, which removed blanket protections of trees in urban areas.
This meant trees without any formal protection on private land could be legally removed, regardless of their age or biodiversity values - even a threatened kauri tree estimated to be several hundred years old could be felled.
It has been well detailed that in the years that followed the RMA changes, Auckland and many other parts of the country experienced a "chainsaw massacre" of sorts as developers rushed to take advantage.
A report this month, and presented today to the council's Environment and Climate Change Committee, showed some parts of Auckland had lost nearly 10 per cent of their canopy cover in only a few years, largely due to development.
While there had been large canopy growth on public land, since blanket tree protections were removed from the Resource Management Act in 2012, came into force in Auckland in 2015, there had been dramatic reductions on private land.
Despite this, the council's Urban Ngahere Strategy advocates for protection of mature trees across the region, which Abel said it was not living up to.
"If the council is just going to let these trees come down, then that strategy is not worth the paper it is written on. If this cluster of native trees is not worth protecting then what will they protect?"
He also challenged the council on the purpose of its climate change plan, if it allowed these trees to be felled.
In late July there were Abel narrowly avoided serious injuries as one of the trees came crashing down right above him.
The Tree Council, which is not linked to or in support of the direct protest action, had approached Auckland Council about three years ago fearing development at the site, suggesting it purchase the land or look at land swap options, including the public reserve down the road which has comparatively few trees.
But nothing happened.
Spokeswoman Dr Mels Barton previously said while the RMA changes meant there was little the council could do to stop the trees being felled, it needed to be "more imaginative".
"It could have been an incredible gift to the people of Avondale, it is a beautiful site, but instead their approach has been a disgrace.
"It illustrates what is happening every day across Auckland, and what already happened here in this suburb in the past - it is a chainsaw massacre."
A council spokeswoman previously told the Herald it had no plans to purchase the property.
Canal Reserve, which was on the same road, already served the community's open space needs, she said.
While the council could not stop unprotected trees on private land being felled, it had various strategies and programmes to plant trees on council land, including the Urban Ngahere Strategy and the Million Trees programme.