Alarming new figures show one in four Australian teenage girls have engaged in self-harm.

The largest-ever survey of youth mental health found 10% of teenagers had engaged in self-harm, and one in 13 had contemplated suicide. One in 40 actually attempted it.

The two-year survey of 6,300 families found a quarter of girls aged 16 and 17 had engaged in self-harm, with one in five meeting the clinical criteria for major depressive disorder.

One in seven children and young people had experienced a mental disorder in the past year and almost one third were suffering more than one disorder.

Health minister Sussan Ley described the report on Friday as “confronting, sad and shocking”.

She was concerned that while ADHD cases were falling, there had been a rise in major depressive disorder.

But it was encouraging that more young people were using support services compared with in 1998, when the Mental Health of Children and Adolescents survey was first conducted, she said.

“As a parent it’s heartbreaking to see these prevalent stories of depression, anxiety, self-harm and suicidal tendencies amongst our young people, let alone as health minister,” Ley said.

“We must recognise in years gone by many of these cases we’re hearing about today would have simply gone unaccounted for while people suffered in silence.”

Ley said she was proud that most young people were turning to sport and other activities rather than drugs and alcohol to address mental health problems.

Technological advances mean the $6.6m federal government-funded survey is likely to be more accurate than when it was first conducted almost 20 years ago, because young people can now participate without parental supervision.

The government says depression reporting rates almost doubled when young people first filled out the survey themselves.

Mental Health Australia chief executive Frank Quinlan said the distressing figures highlighted the need for more information and a national mental health plan involving all levels of government.

“There’s still an uncomfortableness about mental illness that means we don’t treat it in the same way we treat other mainstream health issues,” he said.

“The health minister can’t solve this on her own – we need the minister for employment, we need the minister for social services and we need the minister for defence and treasury and finance to all come together on this.”

An expert reference group set up by the federal government to map out a plan on how to implement the recommendations of a review of the mental health system will report back to Ley in October.

• Readers seeking support and information about suicide prevention can contact Lifeline on 13 11 14 or the Kids Helpline on 1800 55 1800.