Violence, sexual misconduct and disgraceful behaviour are among the 1680 allegations of misconduct made against police staff this year.
New figures released today by police show the complaints - against officers and other employees - related to 1312 incidents from January through until June.
Of the 1004 investigations carried out, 143 were upheld, at least in part.
The most common complaint related to service failure, with 610 allegations over inadequate service, failed investigations, failure to prosecute and failure to turn up.
Unprofessional behaviour came in second, with 364 allegations.
Of those, 295 complaints were laid against frontline police officers over poor attitude, language, harassment, bullying and discrimination.
Overall, the top five allegations were:
This is the first time this kind of information has been released to the public without an Official Information Act request. It is expected to be updated quarterly.
According to separate figures, as of 30 June 2015, there were a total of 11,980 police staff in New Zealand - 9048 constabulary staff and 2932 non-sworn staff.
Complaints by region
In the six months to last June, Wellington police received 40 complaints of unprofessional behaviour - the highest in the country.
That police district is also one of the largest in the country, with - according to separate figures from last year - 775 full-time constabulary and 116 full-time non-sworn officers.
The behaviour of off-duty staff was also included in the conduct report. Overall, around the country, there were 14 allegations of violence, seven of disgraceful behaviour, six of sexual misconduct and three relating to drugs and alcohol.
Police welcome increased transparency
Police said they had nothing to hide, and wanted to be transparent about what complaints were being laid against staff.
Assistant police commissioner Allan Boreham said any complaint was concerning.
"I guess it is heartening to see that it's around service failure, or us not always being professional, or that we have breached some of our official duties, or in really difficult situations like arrests, rather than at the criminal end of complaints."
Mr Boreham said the complaints reflected only a fraction of all the events the police attended.