The government's mental health workforce plan for England, published last month, includes a pledge to recruit an additional 2,000 staff for child and adolescent mental health services (CAMHS) to ensure 70,000 more children and young can access support by 2020/21.
But the British Association of Social Workers (BASW) and organisations representing speech and language therapists, psychologists, counsellors and psychotherapists are concerned that the plan has been developed with too narrow a focus on psychiatry, and is ignoring the role the wider social and health care workforce can play in improving access.
In a joint letter to health secretary Jeremy Hunt and senior health figures, the organsiations said the development of the plan "excludes the majority of professional bodies, charities and experts-by-experience".
The letter - signed by BASW chief executive Ruth Allen and the heads of the British Psychological Society, British Association of Counselling & Psychotherapy, the Royal College of Speech & Language Therapists and the UK Council for Psychotherapy - states that those with mental health problems will continue to miss out unless their organisations are more involved.
"The negative effect on people in England of focusing on a small section of the mental health workforce and setting aside the considerable contribution also made by other sections of the workforce will be great," the letter states.
"We would urge Health Education England and the NHS to engage and collaborate with all professions and experts from the wider mental health workforce moving forward to ensure the strategy provides an accurate and agreed reflection of their potential contribution and provides the best outcomes for service users."
A BASW spokesman added: "There's a real deficit in workforce in children and mental health services, yet social workers have the expertise and experience of working in this specific arena of social care - so BASW believes it makes complete sense that social workers should be central in any dialogue or consultation to address children and mental health services."
The mental health workforce plan is to be funded from an existing £1.4bn extra investment in mental health services to bring greater parity with spending on physical health services.
It includes a pledge that by 2020/21, 95 per cent of children and young people in need of urgent treatment due to an eating disorder are seen within a week and within four weeks for routine treatment.
It also reiterates Prime Minister Theresa May's promise in January that children and young people with mental health problems will no longer be placed in inappropriate settings or far from their family home by 2020/21.
The Department of Health has been contacted for comment.