Teachers will be asked to identify children as young as 11 who are in danger of becoming Neet (not in employment, education or training) as part of a new drive to combat youth disengagement.
Schools will be expected to improve their support for pupils moving from primary to secondary as part of the Assembly government's youth engagement and employment action plan. This will include providing mentors in a bid to "break the cycle" of underachievement among vulnerable children.
The four-year plan comes as figures released this week suggest the number of Neets in Wales reached an all-time high last year.
A population survey by the Office for National Statistics reported that there were 67,900 Neets aged 16-24 in June 2010, compared to 61,700 in June 2009.
There was a huge increase in the 19-24 age group, where 22.4 per cent were classed as Neet in 2010 compared to 19.1 per cent the previous year. Numbers fell in the 16-18 group from 12.9 per cent to 11.3 per cent.
The Assembly government launched a Neet strategy in 2009, but ministers admitted that although a "lot of good work" had been done, dramatic changes to the economy had hampered progress.
Launching the new action plan in the Senedd last week, education minister Leighton Andrews said efforts to tackle the Neet problem needed to go further than just focusing on young people when they reach 16.
He said: "Evidence has shown that support in the earliest years of a child's life is the most effective way of improving life chances, breaking the cycles that can exist for some of our most disadvantaged and vulnerable children and providing a chance to grow, succeed and achieve."
A number of the action plan's 18 points will have a direct impact on schools and teachers. They include specialist training for teachers on how to deal more effectively with pupils at risk of becoming Neet.
From December, new measures will aim to strengthen planning and provision for young people making the transition from primary to secondary school and from education into employment.
Learning coaches have already been introduced for pupils when they reach 14, but that will be extended to younger children.
Neet expert Howard Williamson, professor of European youth policy at Glamorgan University, said teachers have a responsibility to be the "first alarm bell" for pupils at risk of becoming Neet.
"The whole population of children go to school, so there should be a duty on teachers to spot problems that may have an impact on their lives," he said. "It's absolutely sensible, both socially and economically, to get in there as early as possible - prevention rather than intervention."
Rex Phillips, Wales organiser of teaching union the NASUWT, said most teachers see it as part of their role to spot pupils at risk of dropping out of school and would welcome the training.
But he said "appropriate external agencies" should do the follow-up work, not teachers.
A number of preventative measures have already been put in place by the Assembly government, including Flying Start, the foundation phase, and the soon-to-be-launched national literacy plan and the child poverty strategy.