Food prices are up more than 19% over the last year, outpacing the broader inflation rate across the whole economy and adding strain to household budgets already stretched by high energy bills and other price increases.
The latest data showed value sales of own-label goods grew by 14.1% compared to branded product growth of 7.1%.
In the last four weeks, the volume share of own-label sales rose to 63.3% in the fast-moving consumer goods' category, versus 62.1% in 2022.
Earlier this month Tesco, Britain's biggest supermarket group, cut the price of its private-label pasta, vegetable and sunflower oil.
Elsewhere, Sainsbury's has rebranded its entry-level private-label products under a new brand called Stamford Street. The Stamford Street range is anticipated to include approximately 200 SKUs and has already begun to appear on store shelves.
Food retailers have said they expect prices to rise in 2023 overall but with the rate of inflation declining through the year.
On Tuesday, Britain's competition regulator told supermarkets it was looking at their earnings to identify which supply chains it needed to examine more closely as part of efforts to tackle food price inflation.
“Inflation has been a significant drag on shopper spend, so this year, incremental sales are reliant on a short-term boost from well-activated events rather than regular promotional activity," commented Mike Watkins, NIQ’s UK head of retailer and business insight.