Close to £100m was spent on take-home alcohol from supermarkets and grocery stores in Northern Ireland in a 12-week period just before and during lockdown.
While overall consumption is believed to have dropped considerably with the closure of bars, the amount bought in the stores, excluding spirits, jumped 51% compared to the same period last year, according to an international consulting firm.
The figures can be revealed as public health officials encourage people to take a closer look at their drinking habits at home to mark Northern Ireland Alcohol Awareness Week.
And it comes as the Executive announced the phased reopening of bars from July 3, but only inside where "substantial" food is served and table service outside.
"Many of us enjoy a drink, but we need to remember that alcohol is a powerful drug that can seriously damage your health, and also have a negative impact on those around you," said Michael Owen, regional lead for drugs and alcohol at the Public Health Agency.
"It's particularly important at this time, as people are drinking at home, to pause and think about how much you drink."
Kantar Worldpanel, which tracks supermarket and other store sales, said the previously unpublished figures for Northern Ireland "represent alcohol purchased in grocery stores to be consumed at home". Those numbers do not include independent off-licences and there are no readily available, or regularly published, figures available for total sales of alcohol in Northern Ireland, either take-home or at the bar, or both.
According to Kantar, Northern Ireland people bought £96m worth of beer, lager, cider and wine from grocery stores in the 12 weeks to May 17, up from just over £63m during the same period last year.
Households bought 28 million litres of alcohol, an increase from 18 million litres, or 53%.
The 12 weeks includes a period when the bars were still open.
The numbers to a large degree tally with more comprehensive surveys in the Republic.
Nielsen reported that off-sales increased year on year by 66% in the four weeks to May 17, to a total of €140m (£126m).
Based on those figures, off-sales in Northern Ireland are likely running at approximately £45m every four weeks during lockdown, including spirits and from off licences.
According to Nielsen, around 22 million litres of alcohol was sold overall in the Republic during the four weeks, a decrease of 16 million litres from the same period last year. The PHA and Northern Ireland's five Drug and Alcohol Coordination Teams (DACTs) are asking people to check how much they are drinking at home during the shut down.
"The Alcohol MOT tool offers the opportunity to learn more about the number of units you are drinking and highlights whether or not you are putting yourself at risk, and directs you to advice on reducing your alcohol intake," Mr Owen said, adding that 89% of adults in Northern Ireland drink alcohol.
He added: "In a pub or restaurant it can be easier to keep track of how much we're drinking as accurate measures are used, but with these businesses currently closed, people are more likely to 'free pour' at home and fill the glass a bit more than we might get from a measure when we're out, so the number of units is greater than we think.
"Think about how much you are pouring and try your best to measure out your alcohol, enabling you to keep better track of your units.
"It's also very important to have several alcohol-free days during the week. Plan these out, too, so you can keep check on them.
"Remember, being intoxicated could be putting you and others at risk, as your judgment will be impaired and you may not be able to follow the social distancing and hygiene practices that are required to help protect you from coronavirus."
Drinkers can take the test at www.drugsandalcoholni.info/mot