The Greens — in opposition nationally but in 11 of the country's 16 state governments — could hold the key to forming the next government.
The AfD is holding a two-day congress this weekend ahead of Germany's September federal election, which will mark the end of Chancellor Angela Merkel's era.
Chancellor Merkel was due to relax restrictions at a meeting with regional leaders on Monday but a surge in infections has upended those plans.
“I can see a light shining at the end of the tunnel,” Merkel said, but she also urged Germans to be patient and warned against "false hopes."
German Chancellor Angela Merkel is meeting with regional leaders on Tuesday to discuss imposing stricter measures to reduce COVID-19 transmission.