Through the celebrity chef's website, his staff recruited fans as mystery shoppers to check displays of his Italian range. They were urged to take photos of in-store displays of pasta sauces and oils - and promised a free peeler in return.
Oliver's followers responded by posting pictures of the displays on the site. But some users of the website hit out at the multi-millionaire.
One, writing under the name dcc251, fumed: "I know this is done by all companies. It is, however, done by paid professionals, who are expected to be objective and file reports evaluating the overall marketing impact of a product.
"Sainsbury's is paying a mint to Jamie Oliver for their name on this product and in their own marketing."
Sainsbury's said in a statement: "Jamie's Italian range is displayed very well in-store, but we welcome all customer feedback."