Germany must “live up to its historical responsibility with regards to those affected,” said Interior Minister Horst Seehofer.
While Germany already has rules allowing descendants of persecuted Jews to reclaim citizenship, the two decrees that came into force on Friday closed several loopholes that had previously shut others out.
Relatives of people who left Nazi Germany before their nationality was evoked by the regime can now reclaim it under the new decree.
People who previously would not have been accorded German nationality, because their father was a foreigner and whose mother lost her German citizenship under the Nazis, for example, can now also benefit from the new rules.
Sharp rise in applicants due to Brexit
The difficulties for some in using ancestry grounds to claim their citizenship came into focus partly due to the sharp rise in number of applications from Britons evoking Nazi persecution of their ancestors, after the UK voted to leave the EU.
From 43 such applications in 2015, the number had soared to 1,506 in 2018, according to ministry figures.
Seehofer said those who have had their claims rejected would now see them approved.
The ministry stressed that no one should be shut out because the Nazi-era injustice was too far back in time.
Second, third, fourth “and in some cases fifth generation” descendants can apply, said the ministry.
“Persecuted persons and their descendants, who had been previously excluded from naturalization because of the morally unjust legal situation, can now have the opportunity to acquire German citizenship under eased conditions,” said Josef Schuster, who heads the Central Council of Jews in Germany.
“This closes a gap in justice,” he added.
The required conditions will be reduced “to a minimum” comprising “basic German language skills” and a basic knowledge of the legal and social order in Germany, said the ministry.
Unlike under typical citizenship application processes, applicants under these categories would not need to prove that they have sufficient financial means to support themselves.