Half of Scotland's health boards have missed their waiting time target for treating children with mental health issues, according to newly released statistics.

The Scottish Government has set a target of 18 weeks for patients to be treated, with health boards expected to ensure 90% of people are seen within this period.

New statistics show seven of Scotland's 14 health boards failed to make the target.

Mental health minister Maureen Watt said their performance was "not good enough".

The Scottish Government recently announced it would increase spending on mental health provision by £150m over the next five years but the Scottish Children's Services Coalition (SCSC) has called on more investment.

A spokesperson for the SCSC said: "These statistics, which highlight that half our health boards are failing to meet waiting time targets, should act as a wake-up call to the Scottish Government as it consults on its new Mental Health Strategy.

"We know that half of all diagnosable mental health problems start before the age of 14 and 75% by the age of 21.

"As such, it is vitally important that we radically improve mental health services and increase investment in these, with an overall aim of ensuring that children and young people get the help they need, when they need it.

"We need to look at preventing such problems arising in the first place and intervene early to ensure that these young people are able to realise their full potential."

The spokesperson added: "As a coalition we are delighted that the Scottish Government has committed an additional £150m in mental health services over the next five years, and that this is to be partly used to bring down child and adolescent mental health waiting times.

"We would however urge the new Scottish Government and mental health minister to act quickly and increase investment from the current figure of less than 0.5% of the NHS budget."

The newly released statistics showed the number of young people treated for mental health conditions rose by 30% from from the quarter ending June 2014 compared to June 2016.

Mental health minister Maureen Watt said: "The continued and substantial increase in demand for child and adolescent mental health services clearly show that in the past there far too many children who were unseen and whose need was unmet for far too long.

"To respond to this we have doubled the number of psychologists working in children and adolescent mental health services.

"We are also investing an additional £150m over five years and will be publishing a new mental health strategy at the end of the year.

Watt added: "I have been clear with boards that any falls in performance towards the challenging 90% target, or children experiencing long waits, is simply not good enough.

"That's why, as part of our investment, an improvement team is working with some of the boards that are facing particular pressures. Services are being redesigned so that in the future performance is improved."

Watt is the first dedicated minister for mental health since the creation of the Scottish Parliament.