The Department of Health is under pressure to provide support to former patients of neurologist Dr Michael Watt who don't appear on the recall list.
It comes after Belfast Trust officials announced a recall of more than 2,500 patients treated by the consultant - the biggest ever of its kind in Northern Ireland.
The controversy surrounding the senior medic has raised concerns for other former patients who have not been recalled by the Trust.
SDLP deputy leader Nichola Mallon has called for the Belfast Trust and Department of Health to do more to support and care for the "distressed patients".
The North Belfast MLA said: "The priority, rightly, is ensuring that all those on Dr Watt's current patient list are recalled to ensure they have the correct diagnosis, are on the correct medication and correct care plan.
"There is, however, a large group of very distressed people, who were under the care of Dr Watt and have not been recalled, but are terrified that they were wrongly diagnosed and wrongly prescribed for years.
"These patients don't know where to turn to for help. They need reassurance. They need support.
"The pathways for these patients need to be clearly set out and set out quickly.
"These patients are in the dark.
"Everything they thought they knew about their illness and their management of their health has been thrown into doubt.
"Their trust and confidence has been shattered. The Belfast Trust and the Department for Health needs to quickly and clearly set out what help they are providing to these patients."
The Belfast Trust is holding special clinics over the coming weeks to see thousands of patients.
Some are thought to be as young as 14.
Ms Mallon said that patients caught up in the scandal should be reviewed "by the right consultant with the right expertise".
She added: "If this is going to take longer than the 12 weeks set out by the Belfast Trust, we need an honest conversation about that.
"This process must be dictated by what is in the best interests of the patient. Nothing else".
Dr Watt also worked in the private sector and had patients in Hillsborough and the Ulster Independent Clinic.
It emerged last week that the Belfast Trust is still searching for 300 NHS patients.
The Department of Health said: "If patients have concerns they should contact the patient advice helpline."
The advice line is 0800 980 1100.