PSNI Chief Constable Matt Baggott described the situation as "unsustainable", when he addressed the issue at a meeting of the Policing Board on Thursday.
The spend on policing for parades, protests and associated disorder since April has topped £15m and almost 700 officers have been injured in the past year due to public disorder.
Nineteen of them are said to have sustained serious injuries.
The cost of the protests at Twaddell is the equivalent of the annual salary of two nurses.
"There are real consequences to these protests which are damaging all communities," Mr Baggott said.
We cannot tackle the scourge of drugs, anti-social behaviour, or even child exploitation, when people are holding the line night after night.
PSNI Chief Constable Matt Baggott
The chairman of the Police Federation for Northern Ireland, which represents rank and file officers, said his colleagues were working to uphold law and order "in the most threatening circumstances".
Terry Spence added: "Perhaps if the community understood the full and shameful price being paid by its police service, then common sense and dialogue might be seen as the proper way to engage.
"It is the only way to arrive at an accommodation with each other which does not create street havoc, economic disruption, and police injuries."
According to Assistant Chief Constable Will Kerr, 3,500 less arrests have been made in Northern Ireland in the last nine months.
He blames the strain being placed on police resources by public disorder situations.
"The journey between normality and crisis in Northern Ireland is only about 24 hours, because there is an inherent unpredictability of very large numbers of people at an interface and we need a solution to come very quickly," ACC Kerr said.
Work to find solutions to contentious issues like parading and emblems has long been a focus for community leaders, but the restricting of the Union flag at Belfast City Hall at the end of last year sparked weeks of riots - including over the Christmas period.
That was followed by more violence which flared across north and east Belfast this summer, over restrictions on parades.
While a recruitment drive aims to find more police officers to bolster the PSNI ranks, the Police Federation has warned that the numbers are simply not enough.
The current recruitment target of another 100 officers by the end of 2014, and possibly another 380 later, is a totally unrealistic response.
Terry Spence, Police Federation
The Chief Constable has said that police numbers should not fall below 7,000 at the current time.
Meanwhile, the leader of the DUP group that sits on the Policing Board - Jonathan Craig - urged the PSNI to work to increase confidence in policing in the community.
"Pointing out the lack of confidence that exists in some parts of the wider unionist community in policing should in no way be interpreted as a justification for some of the behaviour we have witnessed," he said.
Pointing to issues such as perceived differential treatment in dealing with unionist and republican parades, Mr Craig added: "I have no doubt that the PSNI have reasons for such differential approaches and that these can in most cases stand up to scrutiny.
"Nevertheless, it is incumbent upon the PSNI to actively engage with key stakeholders, including the Loyal Orders on a regular and on-going basis."
All-party talks are set to go ahead later this month, chaired by US diplomat Richard Haass, which will set to address long-standing issues of concern - including the past, parades, protests and emblems.