Experts are "waiting on possibly an avalanche of trauma" in children as a consequence of the coronavirus pandemic.
The stark warning came from Dr Dominic McSherry, a childhood development psychologist at Ulster University.
While Dr McSherry focuses primarily on complex trauma in vulnerable children, he noted that Covid-19 had exacerbated what is known as 'simple trauma' in many young people across Northern Ireland.
"This is where children experience single incidents of trauma that have negative impacts on their lives," he said.
"There's a lot of serious illness for parents and grandparents - more than 100,000 people in the UK currently.
"Below that are hundreds of thousands of children who have experienced the deaths of a family member or one of them becoming very ill.
"We know children get very anxious in relation to any illness with their parents. It's a shock to the core of their security.
"Children may not have been able to grieve properly and we're waiting on possibly an avalanche of trauma. We need to be prepared for it so that we can respond properly."
Local children are 25% more likely to suffer from anxiety and depression compared to young people in other parts of the UK, according to a survey published by the Health and Social Care Board (HSCB) last October. Another study by Queen's University last year found one in five people here met the criteria for Covid-related post-traumatic stress disorder.
These anxieties often manifest within adults and are passed down to children, said Louise Gault, a counsellor for the Belfast suicide prevention charity PIPS.
"For people who have anxiety about going out, Covid is almost self-fulfilling," she added.
"They're almost being proven right in that the world's really dangerous and they better not go out. That's an intergenerational thing and is passed onto kids.
"I have young people coming to me that are generally anxious and they can't really tell you what they're anxious about."
Ms Gault said she used to deal with more adults, but now, working for PIPS, half of her clients are aged 17 or under.
She explained that where teenagers previously sought out help for difficulties with studying or sleeping, a large number of young people were now displaying general anxiety.
"I think part of it is because parents are very aware and they hear in the media that mental health is going to be desperately affected by Covid. We have to look after our kids," she added.
"It's a two-edged sword. I've had a couple of young people drop out of guidance counselling because they really only came because their parents wanted them to, instead of seeing what the child can cope with themselves and learning to build up a tolerance of really difficult feelings and situations."
Dr McSherry said only time and objective research would give an accurate picture of how the coronavirus pandemic had affected young people.
He also stressed, however, that the main findings coming through from preliminary studies were that "behavioural issues are increasing".
"(But) emotional issues for older children have actually improved, which is a strange finding," he added.
A Freedom of Information request to the HSCB revealed that during the first lockdown - from March to June - the number of patients admitted to Holywell Hospital because of mental health or addiction issues rose from 32 to 85.
Childline NI also reported a 25% increase in children contacting its for advice because of maltreatment.
Ms Gault said young people needed to be shown there was hope and light at the end of the tunnel, both in terms of Covid-19 and mental health struggles.
She added: "If they get through to the other side, that is building resilience in that they have coped with this situation. Things do change. Nothing stays bad for ever."