A Labour government will enshrine the right to counselling for mental health problems in the NHS constitution, just as people have a right to drugs and treatment for mental illness, Andy Burnham will promise today.

Burnham, the shadow health secretary, will say at a conference on mental health and wellbeing in Shrewsbury, that mental health is the biggest unaddressed health challenge of the age, costing business £71m a day, or £26bn a year.

He will accuse the government of cutting the mental health budget and abandoning the national survey of investment in adult mental health services, which showed how much was spent annually.

"There is growing evidence of highly vulnerable people being held in police cells and sleeping on camp beds in office space because no crisis beds are available," he will say. "The cost of living crisis is tipping many people over the edge and concerns have been raised over the suicide rate. It is imperative that the openness and transparency the secretary of state speaks of are brought urgently to mental health services so parliament can have a proper debate on what's happening to vulnerable people."

The suicide rate is increasing, Burnham reports, rising from 11.1 to 11.8 deaths per 100,000 population between 2010 and 2011, according to the Office for National Statistics.

Antidepressant prescribing is also rising; there were 4,000 more prescriptions between 2010 and 2011, a 9.4% increase in a year.

Waiting times for counselling, or "talking therapies", are increasing, he will say. More than 80,000 of the 241,250 patients referred for counselling between April and June this year waited for longer than the 28-day target.

In response to a parliamentary question from Labour's Lord Hunt, the parliamentary under secretary of state Earl Howe confirmed this week that a national survey for 2012-13 had not been commissioned and said that current data on spending on adult mental health services in England was not available.

"We are currently working with NHS England to explore the use of data collected as part of the programme budgeting collection as a potential replacement," he said.

Burnham will accuse the government of hiding cuts to mental health spending.

He will say: "Parliament voted for parity of esteem and we've now no way of knowing if that commitment has been delivered.

"All the evidence we hear is that mental health services have been cut further this year and there's a crisis in mental health crisis care. Now the government is trying to hide the reality of what's happening."

A department of health spokesman said: "It's important to know how much the NHS spends on mental health. The old surveys only captured rough estimates of how much the NHS spent on mental health. We are currently working with NHS England to find new and better ways of capturing how much the NHS actually spends. This means there will be better information out there the local NHS can use to see how much they spend compared to other areas.

"We have clearly set out what services the local NHS must provide for people with mental health problems in our mandate to NHS England."