The number of abused children in state care has gone uncounted for 18 months, after years of reporting them.
The Ministry of Social Development has included this number in its annual report since 2010/11. Almost 170 children were found to be abused in state care from 2010 to 2015. But the number was not included in the last report for 2015/16.
Green Party social development spokeswoman Jan Logie said this was "blase and shows an unwillingness to be accountable". She said she believed measuring how many young people are abused by Child Youth and Family caregivers was a key step to stopping the abuse.
"There has been a 25 per cent increase in the young people abused by CYF-approved caregivers since the government started counting so we haven't been on the path to making kids safer.
"It should matter to the Minister how many children and young people are being abused during this time of transition."