Chief Medical Officer Dr Michael McBride believes it could be "years" until the true Covid-19 death toll in Northern Ireland will be known.
He was speaking after the Department of Health announced yesterday that the number of deaths here linked to coronavirus had risen by 34 to 250.
The department outlined that eight deaths had occurred in hospitals on Tuesday and that a further 26 deaths that had been previously unreported had now been added to the official record.
Separately, it was announced last night that the Republic of Ireland had recorded a further 49 deaths.
This took the all-island death toll to 1,019.
Speaking during the daily Covid-19 conference at Stormont Castle yesterday, Health Minister Robin Swann said "we have never walked these paths before" and that there will be more deaths in the weeks ahead.
Meanwhile, the chair of Stormont's Health Committee, Sinn Fein MLA Colm Gildernew, criticised the previously unreported death figures and stated steps had to be taken to "ensure an error like this never happens again".
Dr McBride explained that it will only be "when we see from a distance" in the years ahead that the true impact of Covid-19 will be fully realised.
This will be based on individuals who have died directly as a consequence of the virus, those whose lives were shortened by it and by looking at the data supplied by the Northern Ireland Statistics and Research Agency (NISRA).
"For the purposes of our monitoring and tracking of the spread and impact of the virus, we have seen that our actions and the decisions that have been taken, we have seen a flattening of the curve," he continued.
"We have seen the number of admissions stabilise and begin to decline and we have also seen the number of admissions to intensive care stabilise and flatten and begin to dip."
North Antrim MLA Mr Swann said that he understood that the extra 26 deaths that had previously gone unreported would "cause some alarm" but said that came down to the "timeline" of the NISRA's report.
Mr Swann added that the report of the extra deaths would always have been released to the public.
"The overall number of Covid-19-related deaths recorded by our local Health and Social Care Trusts has now risen to 250," the Ulster Unionist politician stated.
"This is a significant increase which includes the eight deaths which occurred [on Tuesday] and also a number of deaths in recent days which have now been added to the official record.
"I appreciate that this latest overall total will cause some alarm. These daily figures are compiled for surveillance purposes to help us track the virus and keep the public as informed as is possible.
"It's always important to remember that each of these numbers is an individual, a family bereaved and a life lost."
Fermanagh and South Tyrone MLA Mr Gildernew said he will be raising the issue of the previously unreported deaths directly with the Health Minister at today's Assembly Health Committee meeting.
"The scale of the human tragedy of these deaths and the number of families grieving loved ones is staggering and brings home the extent of the pandemic crisis we are facing," he stated.
"More than 1,000 people have lost their lives as a result of this pandemic across the island, including 250 in the north.
"It is deeply worrying, however, that weeks into this crisis that such an error can be made in terms of reporting the number of deaths.
"These are people with families who have been plunged into grief by their loss, not mere statistics.
"The Health Minister and department need to take steps to ensure an error like this never happens again."
Mr Swann also revealed yesterday that testing for Covid-19 will be expanded to frontline workers in the private sector.
He said that employees in supermarkets, the telecom industry and Royal Mail will all now be able to be tested for coronavirus if they think they are eligible as part of the expansion into testing, as well as their families if they are showing symptoms.
"Whilst our priority must remain on helping those who are sick now, as well as supporting the staff who are so heroically looking after them, we must also look to how we will respond to the virus in the days and weeks ahead," he added.
"That will include a rigorous programme of testing, tracing and tracking.
"That is why today I am announcing a further expansion of our testing to now include additional frontline workers and symptomatic members of their households.
"Importantly this now includes frontline workers in the private sector with a focus on staff delivering key medical, energy, utility, transport and food supplies."