Police staff manning Auckland's boundary checkpoints and managed isolation and quarantine (MIQ) facilities are reporting burnout, fatigue and a strain on resources elsewhere.
Many are putting in a lot of extra hours, carrying out extra duties and "it seems never ending to them", the Police Association said.
"Police are the same as everyone else, you can only have so much resilience and it's just running out," said president Chris Cahill.
Deploying police staff outside of Auckland to help with border checkpoints around the Supercity has cost more than $236,125 as of October 1, Police News reports.
Some delegates at the annual Police Association conference said frontline staff were being taken away from "business as usual" to staff special projects and Covid checkpoints.
"The biggest challenge is the huge drain on staff away from core roles for checkpoint duties and Covid hotels. No workgroup is untouched," one person said, according to Police News.
Another said MIQ and border patrols were a huge drain, leading to fatigue and burnout among staff, the magazine reports.
A strain on police resources during the Delta outbreak comes as Auckland CBD residents have reported increasing disorderly behaviour in the area.
"Public drunkenness, meth rages, and opioid comas are now so common that when I see someone lying motionless in the middle of the footpath - all I do is check if they're breathing before carrying on," one resident told the Herald earlier this week.
Auckland Central MP Chloe Swarbrick said police informed her that "their officers, many of whom have been seconded to MIQ and the border, will be back in mid-November".
Checkpoints were established across Auckland's southern and northern boundary on August 31, to contain emerging Covid-19 cases while other parts of the country enjoyed more freedoms.
They have been patrolled by officers ever since, with more than 60 additional officers from around the country deployed to bolster the checkpoints on September 8.
The checkpoints have caused "considerable strain" on staff wellbeing as well as the financial toll, Cahill said.
"When they're away working 10, 12-hour shifts on the checkpoints, which let's face it, isn't the most fun work, standing on your feet all day checking vehicles, you start to run out of steam," he told the Herald.
On top of that, demand for police staff at MIQ facilities grew as an increasing number of New Zealanders became infected with the virus and needed to isolate, and "many of them not happy about being in there", Cahill said.
Like Auckland border breaches, some MIQ residents tried to escape and the responsibility has fallen on police to relocate them, and in some cases, arrest and charge the absconder for failing to comply with the Covid-19 Order.
Cahill said with extra pandemic-related work compounding with existing high levels of family harm and mental health callouts, resources have been under pressure and the workload has had to be carefully juggled.
"It mightn't sound a lot, but when you're talking 600 odd staff in MIQ and at checkpoints, that's actually a fairly decent percentage of police officers and there's certainly something that has to drop off.
"A lot of that has been investigations of minor to medium-type crime, so some assaults, thefts, burglaries, those sorts of things simply don't meet the priority at the moment because the shortage of staff around the country."
Cahill said that has been particularly prevalent in Auckland, where there has been a string of high-profile incidents of violent crime, including gang-related shootings and homicide investigations.
"That's putting a real strain on police."
He said police are "pleased" to see that Auckland's border will re-open to fully vaccinated New Zealanders from December 15, and police will only be required to carry out spot checks.
"That's light at the end of the tunnel for those officers."