Use of force on duty, unprofessional behaviour and service failure were the three top complaints made about Northland police last year.
The latest police professional conduct statistics published online tallies all allegations made during 2018 against the police organisation and its staff.
Northland's police chief said the nature of policing could be volatile and unpredictable, and complaints were an outcome of situations where officers had to balance wants, needs and views of individuals against the need to carry out police duties under the law.
Complaints against police were the lowest in Northland with 102 incidents being reported. The Tasman police district had 107 complaints and Eastern 131.
The police district with the highest number of complaints was Canterbury with 317, followed by Wellington 280 and Auckland City 240.
The police conduct report also recorded if the investigation into the allegation was ongoing or completed, and in the case if the latter if that complaint was upheld.
In Northland the 102 incidents involved 135 staff members with 152 allegations being made.
Last year investigators had completed 74 incidents and upheld 17 complaints in Northland.
For Northland complaints for service failure were 34, use of force on duty 19 and unprofessional 18. There were also three incidents of off duty conduct reported and one incident of using police resources.
Use of force on duty included manual force, oc spray, dog bite, restraints and taser, while unprofessional behaviour covered attitude, bad language, harassment, bullying and discrimination.
Service failure allegations included investigation failure, prosecution failure, failure to return property and inadequate service.
The report noted that numbers of staff varied between districts and that would be reflected in the number of complaints in each district.
Northland District Commander Superintendent Tony Hill said police officers in Northland were held to a high professional standard, as the community would expect.
"We discuss the Police Values and our expectations in regards to them everyday. However, I do acknowledge that, despite having the best of intentions, individual staff members are human and there are some occasions where our staff don't always get it right."
Hill said police took any complaint regarding staff conduct seriously and any information was investigated thoroughly.
"I want to reassure the public that there is a robust process in place to manage complaints around police conduct. Every matter is reviewed to identify any opportunities for lessons that can be learned going forward."
The specific outcomes of complaints were not able to be discussed as there were privacy considerations.
"I can assure you that if an officer's conduct is not in line with Police values we will not hesitate to investigate and deal with the matter appropriately. In general I am extremely proud of the work of Northland Police staff, who work hard each and every day to keep our community safe."
Nationally the report has shown unprofessional behaviour, including poor language, and service failure were behind the most commonly upheld complaints last year.
Nationally the two most upheld complaints related to inadequate service and attitude/language.
The report also flagged cases where self-harm occurred while in custody, confidentiality was breached, unlawful searches were made and a police database was used for an unauthorised purpose.