Merkel drew up the law after some of the 16 federal states refused to implement tougher measures despite a surge in COVID-19 cases and in defiance of a lockdown agreement reached in March.
"This is something new in our fight against the pandemic. And I am convinced that it's urgently needed," Merkel said in her weekly video podcast.
Both chambers of parliament approved the amendments to the Infection Protection Act earlier this week to give the federal government more powers to fight the third wave in the pandemic.
Merkel drew up the law after some of the 16 federal states refused to implement tougher measures despite a surge in COVID-19 cases and in defiance of a lockdown agreement reached in March.
"It should be a quiet Easter, with those closest to you, with very reduced contact. I urge you to refrain from all non-essential travel," Merkel said in a video message, adding this was the only way to help the doctors and nurses fighting the virus.
The clock is ticking for Germany to reverse soaring infections which, according to its top public health official, could jump to 100,000 a day from 20,000 now.
Germany stepped up lockdown measures in December to contain a second wave of infections, which has now turned into a third wave although with fewer deaths.
Germany's struggle to contain a second wave of the coronavirus that has now morphed into a third lies in stark contrast to its successful containment of the first outbreak early last year.
"The British mutant, and this is the difference with the spring, is proven to be more dangerous in children and young people so we need to put the protection of schools more front and centre than with the original virus," she told lawmakers.
The left-leaning ecologists there currently govern together with the CDU, in what could serve as a blueprint for the first federal government of the post-Merkel era.
Germany had previously said it lacked sufficient data to greenlight the jab for those over 65, but Merkel said that had changed thanks to recent encouraging studies.
The document, which was prepared for a virtual meeting of Chancellor Angela Merkel with the 16 state premiers and representatives of pharmaceutical companies and the European Union later on Monday.
Laschet, premier of Germany's most populous state and the self-styled Merkel continuity candidate, won 83.35% of the valid postal votes cast by 1,001 delegates.
"The CDU remains Germany's Europe party," Laschet told reporters, stressing that he wanted his leadership of the party to be marked by dialogue with its grass roots.
Moscow will relax some restrictions from Friday, including fully reopening colleges and specialist education institutions, the mayor of the Russian capital said.
With time pressing, one elderly care home went ahead with first vaccinations for its residents shortly after the doses were delivered on Saturday -- a day before the national inoculation campaign was due to start.