Officials warned ministers they expected "significant underestimates" of the level of domestic violence during the level 4 lockdown, due to limited opportunities to report any abuse.
This is according to a report provided to the Minister of Social Development, Carmel Sepuloni, released today in another tranche of Covid-19 documents.
The report advised the Minister on how best the Government could mitigate the social impacts of Covid-19 and detailed who would be most disproportionately impacted.
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"The Review shows that Covid-19 pandemic is expected to have disproportionately negative impacts on Māori children and young people and other groups of Māori," it said.
It added that Pacific people would also be some of the most adversely affected by the pandemic and the lockdown.
The report has a specific section related to domestic abuse and the concerns officials had about going into lockdown.
"After a sharp initial increase, police callouts relating to family violence decreased to at or below levels normally observed," the report said.
It also said there has been no increase in Oranga Tamariki reports of concern.
But officials said this was unlikely a truly accurate picture.
"These are expected to be significant underestimates of the true rates of family harm, owing to the limited opportunities to report in the context of Alert Levels 3 and 4."
In particular focus of the report was the impact of children living in violent households during lockdown.
"The impact on children is particularly important because of the potential effects over the course of their lifetime," the report said.
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A separate report, also released this morning, warned Children's Minister Tracey Martin that "Children are among those most at risk of experiencing psychological trauma and behavioural difficulties after traumatic events like the Covid-19 pandemic".
Officials noted that this year's budget committed $183 million to family violence services, in recognition of the likelihood that ongoing financial hardship and associated stress may increase the risk of family violence.