People living in Tier 4 Covid areas have been told: "Don't come to Suffolk".
Police have warned visitors to second homes on the county's coast ahead of Christmas the coronavirus guidelines are "perfectly clear" and fines could be issued to rule-breakers.
Resorts such as Southwold and Aldeburgh, which are popular second home towns with affluent Londoners, have reported an influx of people over the last few days.
Tim Passmore, Suffolk's police and crime commissioner, has issued a 'stay at home' plea in a bid to encourage people from making the journey to the county from parts of the country with high infection rates.
He said: "Suffolk is a fantastic place to visit, whether you’re a day-tripper or have a second home here, and we thoroughly enjoy sharing our beautiful county and all it has to offer.
"However, we are living through difficult times and our public services, particularly our hospitals, are being challenged beyond anything experienced before.
"For that reason I would urge all visitors, particularly those with second-homes in the county, to reconsider any plans to visit Suffolk for Christmas and the new year.
"If you are living in Tier 4 the rules are perfectly clear, you should not travel out of the area so please do not come to Suffolk at this time."
London, along with other parts of the south-east, was placed into new Tier 4 measures from Sunday - forbidding travel unless it is for an essential reason.
Pictures emerged on Saturday evening of crowds of passengers at London railway stations, sparking fears the virus could be spread to other parts of the country.
Southwold mayor Ian Bradbury said the town had become "rammed" on Sunday morning, while Aldeburgh residents reported seeing a queue of traffic outside of the resort after the government's announcement of the new tier on Saturday afternoon.
Suffolk police said officers will be issuing fines to those caught breaking the recently-introduced rules.
A spokesman for Suffolk police added: "We must all understand the dangers of the rapid spread of this new variant of Covid-19.
"Most people will want to do the right thing to protect public health and the health of their loved ones.
"We urge everyone to follow the rules and those who blatantly breach the regulations should expect to receive a fixed penalty notice."
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