Many GP practices in Wales are not geared up to provide adequate mental-health services, according to the Assembly's Health Committee.
A review found around two-thirds of surgeries needed more support in order to manage patients with mental-health problems.
The report said witnesses complained of a "one size fits all approach" and that some patients were referred for treatment unnecessarily.
The Committee of Assembly Members (AMs) wants the role of GPs in treating mental health cases needs to be "clarified". It added that the Assembly Government needs to improve the knowledge and skills of primary care staff.
The AMs warned against plans to put vice chairs and directors of local health boards in charge of mental health services as the demands of handling this along with primary and community services would be too much.
A key plan to improve services, the Mental Health National Service Framework, has not been properly introduced according to the committee, and as a result, targets have not been met "because there is no consequence".
The committee suggested a planned reorganisation of the NHS would be a good opportunity to boost mental-health services.