Sandwiches sold in cafes are to be checked as part of a wider investigation into the horsemeat scandal.
The Food Standards Agency (FSA) says 514 products will be sampled as part of its "expanded" survey.
The checks will be carried out by at least 28 local authorities across the UK and will include both pre-packed and loose food.
"This will give us as full a picture as we can possibly have," an FSA spokesman said.
"We became aware that the issue was bigger than just burgers and it became sensible to look into other products too."
Initial checks by the FSA on 2,500 samples of minced beef products including burgers and meatballs found seven products contained horsemeat .
Affected products included frozen spaghetti bolognese sold by Tesco, lasagne on sale at Aldi and burgers sold by the Co-operative.
Further FSA tests will include samples of chilli con carne, cottage pie, ravioli and cannelloni, as well as kebabs, gelatine, and stock cubes.
Initial findings will be released at the end of the month and the FSA will confirm whether it has taken any action in April.
In other developments, Nestle removed Buitoni brand beef pasta meals from supermarkets in Italy and Spain after it discovered traces of horse DNA.
A company spokesman said: "There is no food safety issue, but the mislabelling of products means they fail to meet the very high standards consumers expect from us."
Meanwhile, the House of Commons said four beef products had been withdrawn from its catering outlets as a "precautionary measure".
Tests confirmed the products contained no horse DNA.