Tesco has increased prices on more than 1,000 products in the past two weeks, including staples such as bananas, cheese, pasta and jam, new internal documents seen by PA show.
The supermarket, which has said cutting prices to compete with discounters Aldi and Lidl is a key priority, put up prices by 11% on average during the first two weeks of July.
A five-pack of bananas has gone up 11% from 90p to £1; own brand farfalle, macaroni and linguine pasta have all risen 30% from 50p a pack to 65p; seedless strawberry jam is up 23% to 92p and iceberg lettuces are up 17% at 60p each.
The highest price rise was for Merchant Gourmet puy lentils, up from £1.42 to £3.60 a pack - a rise of 152%.
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Industry sources said prices will go up and down across the whole industry but the size and scale of Tesco's recent rises were notably high.
Supermarkets typically move prices on branded products due to promotions coming to an end, but prices on own-brand food and drink tend to be more stable.
Out of the top 50 price rises for the supermarket, 18 were own-brand products.
The branded items with the biggest rises include Cathedral City Mild Cheddar up 57% to £5.50 for 550 grams; 20-packs of Carlsberg lager up 33% from £9 to £12; Ferrero Rocher chocolates up from £1 to £1.25 and a 5kg bag of Salaam basmati rice now £9 versus £7 previously - a rise of 29%.
The data, which is used internally by grocers to monitor the industry, is provided by Brand View.
Tesco said the rises were due to cost pressures that were hitting the entire market, and pointed out that over the last three weeks prices were cut on 121 items by 24% on average, including own-brand coconut milk, down 55p to 90p, and Tesco frosted flakes cereal, down 20p to £1.
A spokesman said: "Over recent months, cost pressures have continued to build and impact the market.
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"We've worked hard to offset these pressures, and focused on protecting our customers for as long as possible. But, like the wider market, we have had to reflect these pressures in the price of some products.
"For the majority of products that have increased in price over the last three weeks, we still beat or match the cheapest of the Big Four [Tesco, Sainsbury's, Asda and Morrisons]."
Price has been a major factor on the high street in recent years, driven by the rise and rise of discount supermarkets Aldi and Lidl.
Tesco has made its own attempts to move into the discount sector, launching its own discount supermarket Jack's.
Clive Black, retail analyst at Shore Capital, said: "The key journey that the UK supermarkets are on is to narrow the basket with the German discounters, who also move prices up and down. That is a key axis that shoppers undoubtedly notice."