Labour and the Liberal Democrats will on Monday launch initiatives on mental health, with Nick Clegg promising to sign up the NHS to a national “zero suicide” campaign while Ed Miliband highlights the need to switch more NHS spending on mental health to children.

The deputy prime minister will say that every part of the NHS in England should sign up to eliminate suicides in an attempt to cut the death toll of nearly 4,700 people a year, the majority of whom are men.

Some organisations in Merseyside, the east of England and the south-west have already adapted methods from a programme to combat depression in Detroit, in the US, where suicides were sharply reduced from 89 per 100,000 in 2001 to as low as zero among the patient population over the decade.

Now the coalition government will appeal for the NHS, charities and voluntary organisations elsewhere to follow suit.

Both parties have timed their mental health policy launches to coincide with Blue Monday – a marketing invention based on a bogus equation to calculate supposedly the most depressing day of the year. The decision will be controversial because Blue Monday’s media profile has been blamed for trivialising depression.

Clegg is hosting a mental health conference at the offices of the King’s Fund health thinktank, at which he will say: “Suicide is, and always has been, a massive taboo in our society. People are genuinely scared to talk about it, never mind intervene when they believe a loved one is at risk.

“That’s why I’m issuing a call to every part of the NHS to commit to a new ambition for zero suicides. We already know that this kind of approach can work in dramatically reducing suicides.”

The deputy prime minster will, according to a text released before the event, also argue that nobody should be blamed for the existing suicide rate.

“It is doing more in every area of our society to ensure that people don’t get to that point where they believe taking their own life is their only option,” Clegg will say.

The national initiative aims to build on three existing local schemes. Mersey Care in Liverpool, an NHS trust, hopes to eliminate suicides in its area by the end of April 2018, with a programme that includes training for staff to concentrate on the skills needed to prepare “safety plans” with patients and their families. It also has a dedicated “safe from suicide” team, monitoring how at-risk patients are doing.

Project Zero, in south-west England, involves mental health service users in its steering group. The alliance of mental health organisations and other groups is working with accident and emergency departments to identify and support people with suicidal thoughts, exploring how to target high-risk groups, including middle-aged men, and work with police and transport providers to identify areas where higher-than-average suicides occur and understand why that is so.

In eastern England, NHS England is funding four pilot schemes hoping to improve care by giving police, paramedics, midwives and GPs training in talking to people in distress and helping to keep them safe.

Labour’s report highlights that just 6% of the mental health budget is spent on children, even though three-quarters of mental illness in adults begins before the age of 18.

Miliband also calls for an expansion of talking therapies, working towards a 28-day waiting-time standard for access to both adult and young people’s talking therapies.

A 28-day standard, with 80% of patients seen within 28 days, would ensure more people get quicker access to treatment. While the current average wait for adults to access talking therapies is five weeks, in some clinical commissioning groups average waits are up to three months, Labour says.

Miliband also proposes that schools should work together to ensure that all children can access school-based counselling or therapy if they need it, including by giving teachers training in how to help with children’s mental health.