"If we keep this up for a month with all consistency, it can be a wave-breaker in this second wave," Xinhua news agency quoted the Chancellor as saying at a press conference on Monday.
She added that "this of course means four weeks of giving up many things that make life beautiful".
After confirmed cases reached a new daily record of more than 19,000 on October 31, Germany's federal and state governments agreed to tighten restrictions on daily life such as closure of restaurants and bars for November.
Merkel warned that many infections could no longer be clearly retraced.
In 75 per cent of cases in Germany, it was no longer possible to say where a person became infected with with the disease, according to the Chancellor.
On Monday, Covid-19 infections in Germany increased by 12,097 within a day to a total of 545,027, according to Robert Koch Institute (RKI), the federal government agency for disease control and prevention.
The death toll increased by 49 to 10,530.
Merkel stressed that Germany had to return from a so-called seven-day incidence of around 127.8 new infections per 100,000 inhabitants currently to a level below 50.
Therefore, it was necessary to act consistently and "reduce contacts wherever possible".
"The virus punishes half-heartedness," stressed Merkel.
"Everyone has it in their hands to make this November our joint success, a turning point back to pandemic traceability."
If Germany succeeded in slowing down the spread of the virus in the next four weeks, this would create the conditions for a December with "more freedom", she added.