Germany is experiencing a new wave of coronavirus infections, Health Minister Karl Lauterbach said Wednesday, urging the most vulnerable to quickly get their fourth vaccination jabs.

"The announced summer wave has unfortunately become reality," he told Rheinische Post daily.

After weeks of falling new infections, the numbers of cases in Europe's biggest economy are seeing an uptick again.

"Because the current virus variant is very easily transmitted and because almost all precautionary measures have expired, the effect of the summer" in calming a surge in infections was not as effective, he said.

Face masks should once again be worn indoors to prevent transmission, added the health minister.

Germany's seven-day incidence rate of new infections per 100,000 people reached 472.4 on Wednesday. 

Europe's biggest economy began easing coronavirus curbs, including letting unvaccinated people back into shops and restaurants, and allowing larger gatherings, from March. 

The requirement for employees to work from home whenever possible was also lifted in the same month.

The wearing of medical masks was removed from schools and offices, but remains mandatory on public transport.