Yesterday, the number of new cases rose above the 1,000 mark - a level not seen since May 7.
Germany's national disease control center has registered the highest number of new coronavirus infections in a day for three months.
"What we are seeing is a lot of small outbreaks", Health Minister Jens Spahn told reporters.
The situation in Mecklenburg-Western Pommerania is closely watched across the country as it was the first of Germany's 16 states to reopen the school gates on Monday after summer holidays.
Travellers to Germany from high-risk areas were previously required by individual states to stay in quarantine for two weeks, but testing remained voluntary.
"I understand if people are fed up, but they should resist the deceptive idea that the pandemic was never all that serious", he said.
"I'm very effectively conscious that this impinges on particular person freedoms, however I consider that this can be a justifiable intervention", Spahn mentioned.
The minister dismissed arguments by some politicians that people who can afford a vacation should also have to pay for tests themselves.
Spahn said however that that imposing tests was "the safe option".
However, he considered this interference to be "reasonable" with regard to the responsibility for others.
Travelers who refuse tests could face fines of up to 25,000 euros (US$29,600), but the exact amount is up to local authorities, Spahn said. The Robert Koch Institute has recorded 9,175 deaths from over 213,000 confirmed cases - a lower death rate than in many comparable countries.
Since August 1, all travellers to Germany had been able to test for the coronavirus voluntarily and free of charge at many airports and some major train stations.