Date Uploaded: 16/05/2016
This means that teenagers seeking direction on issues that have a crucial bearing on their life chances are relying on people who don't have the necessary expertise.
As many as one in six (17pc) schools are using unqualified personnel for guidance counselling every week.
That is up from 12pc four years ago, when the cuts were made, and a new report expresses concern about the "substantial" number now involved,
A widening class divide in terms of the availability of career guidance and personal counselling to students is also exposed, following an independent audit carried out on behalf of the Institute of Guidance Counsellors (IGC).
Fee-paying schools have more than covered the cuts by buying in professional expertise for their pupils. By contrast, at the other end of the spectrum, disadvantaged communities - whose children are most in need of support - are suffering the biggest loss of service.
IGC president Betty McLaughlin warned: "There is a socio-economic hierarchy in the provision of hours for guidance counselling, where those who can afford to pay for it receive the greatest benefit."
The findings emerged in a survey conducted in more than half (52pc) of the country's second-level schools and colleges of further education in recent months. It is the fourth such audit tracking the impact of the withdrawal of the ring-fenced allocation for guidance counselling in September 2012.
As a result of that measure, principals have to provide guidance and counselling from within their standard teaching hours allocation. This has led to a disjointed service, with a small number of schools employing no guidance counsellor.
Although the overwhelming majority of schools continue to have accredited guidance counsellors on their staff, many of these are diverted to teaching for some or all of the working week to cover other gaps.
Overall, there has been a 28pc loss in the number of hours that schools allocate to the service, which covers both career guidance and counselling for students who need support on personal issues.
But those schools which are in the Department of Education's DEIS scheme for disadvantaged areas - one in four second-level schools - report an above-average cut of 33pc.
Meanwhile, fee-paying schools are actually providing 1.9pc more hours, because they can afford to pay for it.
Almost almost one in four (22pc) fee-paying schools are buying guidance and counselling services privately.
Crucially, there has been a 54pc drop in the time spent on one-to-one sessions with students. This is down from an average of 12 hours a week spent by a counsellor on this work in 2012 to less than six now.
That has improved from the 59pc drop reported in the first year of the cuts, as schools made efforts to prioritise this aspect of the service.
But Ms McLaughlin described the drop in one-to-one counselling as "catastrophic".
There is also a growing reliance on external providers, usually private or retired guidance counsellors or other professionals, such as therapists or psychologists, or representatives of a range of organisations.
The report states that while this may be done with the best intent, it expresses concern about the absence of an over-arching quality system.
It warns: "The use of this practice is high-risk for students and there is a need to address it as a matter of urgency."
A partial restoration of cuts to guidance counselling is due in September, although it remains to be seen how schools will allocate the extra hours.
The new Programme for Government promises further restoration, but the detail has not been released.
Journalist: Katherine Donnelly