The cost of poor secure beginnings - New Zealand

From 2001 to 2017, approximately 1 million babies were born in New Zealand. • Dayspring estimates that given maternal mental health services proceed on their current course, at least 60,000 (1 out of 17) of those children will experience detrimental mental health issues over the next 25 years due primarily to attachment disorders occurring in the first 1000 days of their lives • Dayspring estimates the cost of addressing the resulting fallout of behavioural, social, medical and psychiatric issues later in life to be between $2 and $4 billion each year. I need to verify these assertions. Can anyone help hunt down the New Zealand data that might back them, please?