Young people are waiting months to get mental health follow-ups after asking for help and a government inquiry into the sector is urgently needed, the Green Party says.
But the Government says the figures are the same as they've been for years and work is already being done.
DHB figures show nearly 3300 children and youths - or 26 percent of all youth cases - had to wait longer than eight weeks to get a second appointment after seeking help in the 2014-15 year, Fairfax Media reports.
Green Party Co-Leader James Shaw said those numbers proved an urgent inquiry into the mental health sector was needed.
"Mental health services are struggling all around the country because of government cuts to the overall health budget, and our vulnerable young people are paying the price," he said.
"New figures released by the coroner last week show that New Zealand has the highest youth suicide rate in the OECD, and I think it is unacceptable for young people to be waiting this long to get the help that they need."
The Ministry of Health says it has increased funding for mental health services by about $300 million since 2008 - from $1.1 billion in 2008-09 to 1.4 billion in 2015-16.
But opponents say increasing demand in the sector and inflation mean the budget has actually fallen in real terms.
Health Minister Jonathan Coleman said he didn't agree there was a need for an inquiry.
"Overall the sector provides high quality mental health services for New Zealanders - from prevention, through to primary care and specialist services," he said.
He said nationally, the percentage of child and youth patients waiting more than eight weeks had not significantly changed in the past four years and the Government still expected urgent cases to be dealt with within 48 hours.
"Nationally 91 percent of cases are seen in less than eight weeks," he said.
The Government was currently evaluating the cross-agency Youth Mental Health Project set up in 2012.
But Dr Coleman said suicide rates were too high.
"Suicide rates have remained consistent in recent years when you look at the population as a whole: 12.32 per 100,000 this year is lower than 12.65 in 2010-11," he said.
The Government had put $25 million behind a suicide prevention plan in 2013 and was currently working to develop a new strategy, he said.
Depression Helpline (8am to 12 midnight) - 0800 111 757
Healthline - 0800 611 116
Samaritans - 0800 726 666 (for callers from the Lower North Island, Christchurch and West Coast) or 0800 211 211 / (04) 473 9739 (for callers from all other regions)
Suicide Crisis Helpline (aimed at those in distress, or those who are concerned about the wellbeing of someone else) - 0508 828 865 (0508 TAUTOKO)
Youthline - 0800 376 633, free text 234 or email firstname.lastname@example.org
What's Up (for 5-18-year-olds; 1 pm to 11 pm) - 0800 942 8787
Kidsline (aimed at children up to 14 years of age; 4pm to 6pm weekdays) 0800 54 37 54 (0800 kidsline)