Politicians will use a Holyrood debate to urge the Scottish Parliament to back a public inquiry across all NHS Tayside mental health services.
Bosses at the health board have ordered an independent inquiry into a psychiatric unit which turned away a man seeking help who then took his own life.
The inquiry was announced after Labour leader Richard Leonard raised the case of David Ramsay at First Minister’s Questions last week.
Mr Ramsay, 50, took his own life in 2010, four days after he was twice rejected for treatment at the Carseview Centre at Dundee’s Ninewells Hospital.
Now Labour wants a full public inquiry into mental health services across the whole region.
The party highlighted that cases of concern would fall outside the current review, including that of Lee Welsh, who took his own life in 2017.
Mr Leonard raised Mr Welsh’s case during his conference speech in March when he first backed the calls for a public inquiry.
Labour health spokesman Anas Sarwar said: “Holyrood must listen to the families of Tayside and back a full public inquiry into mental health services.
“The tragic case of David Ramsay was not an isolated incident. There are clear problems with mental health services across the region. It is not confined to one unit in one hospital.”
He added: “These families deserve answers. Only a full, independent public inquiry can deliver that.”
Families who have been affected by mental health services in NHS Tayside will be in the public gallery to watch the debate.
Health Secretary Shona Robison said: “I welcome the leadership being shown by NHS Tayside in commissioning an independent inquiry into mental health and suicide prevention services in the region.
“The inquiry must capture the concerns of patients and families who have felt let down by services.
“Not only should patients and families be able to participate, they should also have the opportunity to input into the inquiry’s terms of reference.
“The inquiry should also help ensure that recommendations from recent Health Improvement Scotland and Mental Welfare Commission inspection reports are fully implemented.
“The Scottish Government will give this inquiry our full support.
“If I believe it is not meeting aspirations, is being hindered in any way or lacks appropriate independence, I will move to strengthen the inquiry using existing statutory powers.”