The Independent Police Conduct Authority is investigating delays in police responses to a potentially significant number of child abuse cases in Wairarapa.
A Masterton judge last week criticised police over a two-year delay in prosecuting a 45-year-old man for assaults on his two daughters in 2006 and 2007.
IPCA chair Justice Goddard says the Masterton case reflected wider issues with the police response to allegations of child abuse in the region, extending back to at least 2006.
The authority's investigation, and a police inquiry under its direction, will consider who was aware of issues with management of child abuse cases and what they did in response.
It will include the review of child abuse files, questions of neglect of duties, compliance with policies and general instructions, the adequacy of existing policies and questions of supervision and oversight.
Police admit they have failed some Wairarapa child abuse victims, their families and the community.
The Wellington policing district has been trying to clear a backlog of 108 cases, mainly in Wairarapa, since December last year. Thirty arrests have been made to date.
Acting Wellington district commander Superintendent Gail Gibson told Checkpoint on Wednesday police will co-operate fully with IPCA inquiry, saying there is no excuse for the unacceptable backlog.