The Police Association says it's costing tens of thousands of dollars a day for the large-scale police response at Ihumātao.
More than 100 police have been at the standoff with protesters since they removed occupiers off the land on Tuesday.
Police are unable to indicate costs yet and won't say how many staff have been involved.
"The number of staff present at any given time can vary with staff being regularly rotated on a shift basis, but the general police presence has remained around the same since the Tuesday," a spokesperson said.
"It is fair to say that an operation of this nature and spanning over a number of days does involve a significant amount of police resources, however, police in Counties Manukau have the support and cooperation from staff from across Tāmaki Makaurau - (Auckland City and Waitemata Districts) - to ensure there remains sufficient police officers as deemed necessary."
The protest is in its fifth day today, and the police say they don't have a timeframe for how long they will remain onsite.
Figures released under the Official Information Act show the cost of $112,490.10 for 101 police to manage protesters around a two-day weapons conference in 2017.
One hundred and sixty staff covering a two-day oil summit last year cost police over $180,000.
The head of the Police Association, Chris Cahill, said it's worth paying for but does put pressure on budgets.
"The police would have to confirm what it's costing but this will be costing tens of thousands of dollars on a daily basis to police this but that's the cost of living in a democracy. It's important that people can protest about issues they feel very strongly about and it's important the peace is maintained while that goes ahead."
He said officers had had to come in from their days off or had been drawn away from their other duties.
"Police aren't sitting around waiting for stuff to happen, there's always jobs for them to attend, calls for assistance. There'll be some real pressures on that, there are less people out there being able to do those normal roles and while police will be calling staff in and trying to bolster that it has to have an impact."