Northern Ireland’s mental health service is being “starved” of funding during the power-sharing logjam, campaigners said.
Lobbyists representing the under-pressure sector are to meet Westminster MPs and peers later seeking action on the worsening crisis.
More people have died through suicide since the 1998 Belfast Agreement was signed than during the entire Troubles.
David Babington, chief executive of Action Mental Health charity, said: “The rest of the UK needs to understand that while we in Northern Ireland have endured over a year with no functioning government, our health service is being starved of funding and decision-making, and we are seeing a deeply worrying rate of suicide.
“It’s hard to believe that more people have now died through suicide than were killed in the Troubles, but the statistic is very real and so is the suffering taking place here.
“This cannot be allowed to continue.”
The delegation is led by Action Mental Health and the Mental Health Foundation.
Talks to restore the Executive collapsed last week and the advocates will demand that Westminster acts quickly to deliver mental health priorities.
Initiatives with cross-party support include a regional trauma service to address the mental health legacy of the conflict.
Mr Babington asked: “Where is the duty of care to the people of Northern Ireland? Moreover, where is the £50 million in extra funding for mental health which was promised nearly a year ago?
“Is anyone in charge?”
The money is envisaged as part of the DUP’s £1 billion deal with the Conservatives in exchange for their support in key Westminster votes.
Head of the Civil Service David Sterling has said his officials needed policy directions from ministers before spending decisions could be taken as part of certainty about the overall budget for Northern Ireland.
Northern Ireland Secretary Karen Bradley is under pressure to address issues like setting a budget and rates bill and is due to update Parliament on Tuesday.
Mr Babington added: “We have been calling for the appointment of a mental health champion to work across government in Northern Ireland to tackle the mental health crisis for years.
“This appointment is more pertinent now than ever in the face of ongoing political deadlock. “
He said Northern Ireland has a 25% higher overall prevalence of mental illness than England, one in five adults have a mental health condition at any one time.
“People are dying and this is simply unacceptable.”