Germany is struggling to contain infections following the country’s glacial vaccine rollout. The country’s seven-day average of cases per 100,000 people rose to 166 at the weekend, according to figures from the Robert Koch Institute (RKI).
As the number of cases continued to rise, Ms Merkel imposed further lockdown restrictions until mid-April.
But as infections are still increasing, Finance Minister Olaf Scholz warned restrictions could be imposed until at least June.
Mr Scholz told Bild am Sonntag: “We need a timetable how to get back to normal life, but it must be a plan that won’t have to be revoked after just a few days.”
He added how the federal government should be able to outline “clear and courageous opening steps” for summer allowing restaurants to adjust reopening plans and summer holidays.
The Finance Minister said steps would also clarify when visits to concerts, theatres and football stadiums would be possible.
This week, Germany’s upper house of parliament approved a law to give Ms Merkel’s Government more powers to fight a Covid third wave.
The amendment to the Infection Protection Act enables the national Government to impose curfews between 10pm and 5am, as well as limiting private gatherings, sport and shop openings.
Schools will close and return to online lessons if the virus spread exceeds 165 cases per 100,000 residents.
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She told ZDF television: “This law has a serious design flaw.
“This law will not bring down infection figures.”
Other minister-presidents in Germany shared their concern over the emergency brake.
Hesse’s Prime Minister Volker Bouffier, of the Christian Democratic Union party, said the exit restrictions were “constitutionally problematic”, particularly with the planned school closings.
More than 80,000 people in Germany have died from the virus.
Doctors have warned that unless action is taken, intensive-care units may struggle to cope.
Germany has also seen growing unrest over lockdown measures and thousands of anti-lockdown protesters demonstrated close to parliament this week.
Police broke up demonstrations at the Brandenburg Gate and more than 150 people were arrested for breaking Covid rules and also attacking officers.
Officers added they had fired pepper spray when protesters tried to get through a barrier at the gate.