Teachers need to make their pupils more resilient in the face of difficulties and boost their self-esteem, according to Assembly government guidelines.
The new advice, which stresses the importance of tackling and understanding the emotional and mental health problems of pupils, is part of a push to promote a wellbeing agenda in schools.
Called Thinking Positively, the advice says all teachers should aim to create an "emotionally healthy school", which will lead to improvements in learning, behaviour and attendance. Following such an agenda, it says, will stop teachers dropping out of the profession after becoming disillusioned with poorly behaved, unhappy pupils.
But teacher critics believe increasing pressure on schools to promote wellbeing risks undermining their main role: children's learning.
There is also some disquiet over proposals from Estyn, the inspectorate, to make wellbeing one of the key components of assessing school performance from 2010.
Andrew Strong, head of Llanbister Primary in Powys, said learning could be compromised if teachers concentrated on wellbeing.
"If the Assembly government insists that a school creates a further layer of policies and documentation, there is a danger we will fail to focus on what can truly enhance children's wellbeing, and that is giving them the tools to achieve their potential," he told TES Cymru.
A final version of the guidelines will be sent to all schools this summer, after consultation. They will advise schools to ensure their policies and initiatives "comprehensively" promote wellbeing, and that pupils should have their say.
"Developing an emotionally healthy school, in which all pupils have the necessary skills to thrive, has implications for every aspect of school life," they say.
The guidance also says teachers should be aware of major influences on emotional health - such as bullying, bereavement, relationships and substance misuse - and know how to deal with them. Above all, teachers should help to make pupils more "resilient" by improving their confidence and self-esteem.
But the guidelines also contend that the pursuit of wellbeing will not involve extra work for teachers if they work more effectively.
Similar moves to introduce a wellbeing agenda in England have met with criticism. Dr Carol Craig, founder of the Centre for Confidence and Wellbeing in Glasgow, said schools and teachers should not be the "main agents" of children's wellbeing. "We have real reservations about the idea that we should be turning schools into centres of wellbeing and downplaying the role of education," she said.
Dr Craig added that schools risked creating an over-protective environment and shielding children from negative experiences if they focused on constant praise and raising self-esteem. "Far from improving wellbeing, this could undermine it further," she said.
Earlier this month, Dr Craig made national headlines when she told an Association of School and College Leaders conference that constant praise was turning a generation of children into narcissists.
Gareth Jones, secretary of ASCL Cymru, said: "In my experience, the vast majority of schools offer a very high standard of pastoral care already. It's not just an add-on service; it occurs in every classroom."
He said schools must not create a "false environment" by shielding children from tough experiences. "You've got to provide support, but it must be appropriate," he said.