Businesses should have an employee who is trained to help workers suffering mental health problems, Nick Clegg said today.
The Deputy Prime Minister wants firms to have a dedicated member of staff who could offer support and advice, similar to workers trained in first-aid.
He said: "I am calling on every employer large and small to do a mental health stock take.
"Too many people suffer in silence with mental health issues. Employers are well placed to recognise warning signs and signpost their staff to support.
"Seventy million working days are lost as a result of mental health issues every year, costing business £1,000 every year for each employee.
"Managing mental health at work well can save around 30% of these costs - businesses cannot afford not to take mental health seriously."
Mr Clegg said conditions such as depression and anxiety cost Britain's economy £30 billion a year.
But a survey two years ago showed seven out of 10 businesses did not have formal mental health policies in place.
The Liberal Democrat leader was speaking as the Government published its implementation framework for improving care and tackling the stigma surrounding the illness.
Its No Health Without Mental Health strategy outlines how employers, schools, local councils, housing organisations, voluntary groups and healthcare bodies can promote good mental health.
MPs were praised last month after several spoke of their own battles with depression during a House of Commons debate.
Labour MP and former defence minister Kevan Jones called for more resources to help MPs fighting the condition.
He said: "Like a lot of men, you try and deal with it yourself. You don't talk to people. First of all it creeps up on you very slowly.
"I think in politics we are designed to think that somehow that if you admit fault or frailty you are going to be looked on in a disparaging way both by the electorate but also by your peers as well."
Care Services minister Paul Burstow said today: "Mental health is everyone's business.
"It is fundamental to all aspects of life - our physical health, our work, our relationships and to achieving our potential.
"The impact of poor mental health can be devastating for individuals and their families and also has a major impact across the economy."
He added: "If we are to improve the nation's wellbeing, organisations from across society need to act as catalysts for change in their communities.
"This framework provides the practical guidance to help make this happen and I am delighted with the support it has from across the mental health sector who have worked so hard on producing this with us."
Centre for Mental Health chief executive Sean Duggan said: "The mental health strategy points to a clear need for a shift towards intervening early when people first experience mental ill health, for action to reduce inequalities in physical and mental health and for support to those with mental health conditions to achieve recovery on their own terms.
"The framework gives organisations across the country a clear message about where to start in making the major changes we need to see to improve the life chances of people facing and living with mental ill health."