Private COVID-19 testing companies will face £10,000 fines for taking advantage of holidaymakers as 91 are removed from the government's approved list following a review.
Health Secretary Sajid Javid said following a review by the Competition and Markets Authority into the private testing market, 135 providers have also had their inaccurate prices corrected.
"They will be removed from the list if they advertise misleading prices again," he said.
"It is completely unacceptable for any private testing company to take advantage of holidaymakers and we are taking action to clamp down on cowboy behaviour."
Mr Javid asked the competition watchdog a month ago to investigate the PCR test market over concerns of "exploitative practices" and vastly different costs to travellers who must take the tests on return to the UK.
Passengers complained of significant price differences and levels of service from the more than 400 firms offering the tests.