No new deaths with coronavirus in Northern Ireland were reported on Tuesday.
This is the first time since the pandemic took hold in late March that the daily figure has been zero.
Health minister Robin Swann said it was “a clear sign of progress” but warned against complacency.
The Department of Health figures referred to no new deaths in the last 24-hour reporting period, nor newly notified deaths, leaving the total in the region at 514.
However, the daily update did record a further 28 confirmed positive cases of the virus, bringing the total number in Northern Ireland to 4,637.
The number of deaths is just a fraction of the potential 14,000 warned of by Mr Swann in March before strict social distancing rules were introduced to stem the spread of the virus.
It comes just 24 hours after the Republic of Ireland reported no new Covid-19 deaths on Monday.
Mr Swann told Stormont’s daily press conference: “We all have been waiting for a day like this”.
“I do believe it is a clear sign of the progress that has been made in the battle against coronavirus, however I have to emphasise a serious note of caution,” he said.
“There are no grounds whatsoever for complacency – that would be insult to all those who have sadly lost their lives and to all those who are mourning them.
“Covid-19 is still infecting people in our community, sadly there will be more lives lost in the days and weeks ahead.
“However there is a clear downward trend in the rolling average number of cases and deaths that we are reporting.”
He added: “If people get it into their heads that this emergency is over, the consequences will be catastrophic.”
“A second wave of the virus is also expected in the months ahead so we must keep our defences up.”
Deputy First Minister Michelle O’Neill also welcomed the news and warned against complacency.
“Let’s keep working together to have more days like this,” she tweeted.
“This battle is not over and we cannot afford for a single person to become complacent to the threat posed by this deadly virus.”
Earlier it was warned that some Stormont departments could have run out of cash before the end of July due to the cost of battling the pandemic.
Five departments were affected and one may have exhausted its funds as early as June 19.
Finance minister Conor Murphy introduced a technical mechanism at the Assembly in Belfast authorising continued spending before more action by lawmakers in the autumn.
The administration has been using millions of pounds to tackle the coronavirus outbreak.
Business tax reliefs and special grants for under-pressure hoteliers and publicans are among extra costs racked up in a bid to keep the economy on life support.
On Tuesday, Mr Murphy told the Northern Ireland Assembly: “Having examined the options the only viable solution is the Assembly’s approval for a further Vote on Account.
“This will provide authority for departments to continue to spend until the detailed Main Estimates can be debated later in the year.”
The Sinn Fein minister also envisaged major challenges arising from Brexit. The transition period is due to finish at the end of this year.
Mr Murphy has said the country more widely faces severe recession due to the coronavirus pandemic.
Northern Ireland has taken its initial steps out of the Covid-19 lockdown, with the reopening of garden centres, churches for private prayer and golf courses.
However, many businesses will not be permitted to reopen until later in the year.
The Executive has published a five-stage plan for recovery, but this does not give indicative dates.
Mr Murphy told the BBC: “We recognise inevitably businesses will suffer and jobs may go, but we’re obviously trying to mitigate against that as best we possibly can.
“I think it is going to be very severe (a post-pandemic recession) and what we have to take into account is the impact of Brexit – that was something that was always going to be very economically challenging for us.”