Almost four in 10 workers in Wales have called in sick because they have felt stressed and unable to cope with work, according to a Samaritans survey.
The WorkLife seminar in Cardiff will be one of 18 throughout the UK
And a fifth of those surveyed said they worked up to two hours extra for every 24 hours they were at their job.
The charity is holding a road show offering training to help managers spot staff who are feeling stressed.
The CBI Wales said: "Anything that supports either employers and employees in this area is to be welcomed."
Independent research commissioned by the emotional welfare charity revealed workers in Wales were most likely to quote stress as the reason they were calling in sick.
A further total of 19.5% of Welsh workers said they worked an average one or two hours over their contract per 24-hour working day.
And 13.1% of workers in Wales were only behind their counterparts in London and Northern Ireland in saying they worked up to four hours over their hours, the study of more than 1,500 people across the UK found.
The Samaritans said its survey showed a third of UK workers cannot get to sleep at night through anxiety and three-quarters cannot "switch off" when they leave their office.
It has devised a series of workplace training courses, called Worklife, to give managers what is says is the "active listening skills" to help a stressed colleague feel valued.
Jonathan Moran is hosting a seminar for about 20 firms in Cardiff on Tuesday to explain what the courses involve.
He said: "It's not about making mangers into counsellors but about making them aware of the warning signs of stress and giving them the confidence to deal with it.
"We look at it as first aid in emotional health because managers are coming into contact with this on an almost daily basis.
"A firm's human resources department can only get involved when someone is on long-term sick. We know the benefits a short-term conversation with a colleague can have."
CBI Wales' head of policy, Emma Watkins, said anything that helped staff to deal with stress was to be welcomed.
She said: "Stress can be very difficult to define and people react to stress in different ways. More firms have stress management policies, whether formal or informal.
"So more information and support that can be supplied to minimise the rise in stress is useful."
Ben Cottam, Welsh Policy Development Officer at the Federation of Small Businesses in Wales, said its own membership survey showed that employers considered their employees to be their main business asset.
"Anything that can create the right environment to make staff feel rewarded, to feel valued, has to be welcomed," he said.