Prime Minister Viktor Orbán said migrants cannot be allowed in, and they should not be privileged by a legal status.
In an interview on Monday, the prime minister said, "we are doomed" if they entered, and "there is no way back".
Before the migrant crisis, Germany "was the strongest state in Europe, but migration destroyed it", he said in the Pikk Extra programme streamed on daily newspaper Magyar Nemzet's YouTube channel.
Some may argue that migration did not drain Europe of its competitiveness, "but that things are interconnected", he said, adding that German identity "was shaken when they took in so many migrants ... and said that Islam is part of German culture."
"We must learn from this mistake," he said. "The Germany that existed before they were allowed in is over, because this is now their Germany too," he added.
PM Orbán said he was "upset" about the issue since "I'm usually a gentle person; even pious, and I try to agree with everyone". Nevertheless, he added, migrants "cannot be allowed here and can never be accepted; they must not be given any legal status because ... there [would be] no way back."