She said: "Only reintroducing PCR tests after two days home isn't sufficient as a precautionary approach as it leaves far too many gaps in the system.
"People can still travel on busy planes, wait in busy departure or arrival halls, then travel home on buses, trains or the tube, all without being tested.
"We know from previous waves and variants that the virus spreads via other countries and via indirect flights, not just directly from the countries most affected - which is why early testing from all countries is vital.
"But, once again, the Government seems to be leaving major gaps in the travel testing regime. They mustn't make the same mistakes again.
"Until we know more about Omicron and its interaction with our vaccines, the Government needs to take swift and sensible measures to stop it spreading into the UK."