The measure, which will come into force on April 10th, is expected to affect mostly German or EU nationals and residents, as the European Union has already banned all arrivals from outside the bloc.
It applies for all modes of transport, whether plane, boat, car or train.
Workers in the health sector living outside Germany in border regions will be exempted from the restriction, which will also not apply for business travellers or technicians entering for a short period of time.
Chancellor Angela Merkel's government had decided on the toughened rule during a cabinet meeting focus on the battle against the coronavirus pandemic.
Since March 16th, temporary border controls have been carried out on the borders with Austria, Switzerland, France, Luxembourg and Denmark.
In border regions where there are no controls, Germany's federal police use the existing search and control instruments. This means that people entering from these areas can also be sent to quarantine or deported back if they are approached by the police within a 30-kilometre radius of the border.
During the same meeting, which is ongoing, ministers agreed that 100 percent of loans made by banks to small- and medium-sized firms will be guaranteed by the state.
The federal government will stand fully behind €500,000 of lending to companies with up to 50 employees and €800,000 for larger ones, upping its guarantee level from a previous 80 percent for large firms or 90 percent for smaller ones.