A new testing programme is to be introduced to UK takeaways after the Food Standards agency found 43 out of 145 lamb takeaways were wrongly described.
Takeaway shop owners have also been warned that they face fines of up to £5,000 if food is found to be mislabelled.
In its investigation, the FSA studied 145 lamb takeaways and found that 25 contained only beef (which is cheaper), according to the BBC. Others contained chicken and turkey.
The watchdog has now said that local authorities must test 300 samples of lamb from takeaways, from May onwards.
The results come after consumer firm Which? conducted tests in London and Birmingham, and found that up to 40% of lamb takeaways contained other meats. In Birmingham, 16 of 30 samples contained meat other than lamb, while in London this was true for eight samples.
Which? has now launched a "Stop Food Fraud" campaign, calling on the government to take further action, including enforcing recommendations made in the wake of last year's horsemeat scandal. None of the samples tested in this investigation were found to contain horsemeat, however.
Chief operating officer at the FSA, Andrew Rhodes, said: "Prosecutions have taken place against business owners for mislabelling lamb dishes, but the recurring nature of the problem shows there needs to be a renewed effort to tackle this problem. Clearly the message isn't getting through to some businesses."