Larger trolley shops and an increase in prices have driven Northern Ireland grocery sales up by 6.8% compared to the same period last year.
And over the most recent 12 weeks, sales of products like alcohol and hair dyes were up - reflecting the prolonged closure of bars, restaurants and hair salons.
The report by information company Kantar said that of the main supermarkets, discounter Lidl was leading the way in sales growth with a rise in sales of 10.3%, upping its share of the market by 0.2% to 6.2% this year.
But Tesco, which has 56 stores here, still holds the top spot with a share of 35.3% of the market followed by Sainsbury's (17.2%) and Asda (16%). Sainsbury's has 14 stores here, and Asda 17.
Emer Healy, retail analyst at Kantar, said: "The Northern Irish grocery market experienced growth of 6.8% during the 52 weeks to July 12, 2020. Sales accelerated by 17.1% in the latest 12 weeks as lockdown restrictions remained in place for the majority of the period. Sales at Asda were up this month by 1.6% thanks to its customers making the biggest additions to their weekly food shop, with basket sizes growing by 15.3%. However, growth is behind its closest rival Sainsbury's, which increased sales by 7.4%. Sainsbury's success was driven by shoppers making larger trips, up 7.2%.
"Tesco, which holds the biggest share of the market, grew its sales by 7.5% year on year, adding 0.3 percentage points of share this period. Shoppers continued to buy more when in store, with volumes up 7.6% on average, and prices were 1.5% higher than this time last year.
"Tesco was once again the only retailer to attract new shoppers in the past year.
"Lidl maintains its crown as the best performing retailer - increasing its sales by 10.3% year on year and bringing its market share to 6.2%, gaining 0.2 percentage points. Higher average prices in store, up 1.8%, and larger shops, which grew by 10.9%, both contributed to the retailer's strong numbers this month.
"Shopper trends in the most recent 12 weeks reflected Northern Ireland's continued lockdown restrictions. We saw sales of hair colourants grow by 83% as shoppers tried to replicate the work of closed hair salons and take-home alcohol sales were also boosted, growing by 73.5%, as pubs and restaurants remained closed until July 3."
The figures were released as footfall figures to high streets, retail parks and shopping centres went up last week. According to Springboard, footfall across NI increased by 9.4%, higher than the national average of 4.4%.
High streets here experienced an 11% rise last week, with retail parks and shopping centres seeing footfall grow by 1% and 4.3% respectively.
Springboard insights director Diane Wehrle said retail growth was positive news for the sector though there was not yet conclusive evidence of the impact of face coverings on footfall.