The Guardian said many are in long-term care facilities in eastern and southern Europe and in Asia. A 2011 study found 7,146 in Hungary, and experts say more than 3,000 are in the Czech Republic and 600 are in Slovakia.
German elderly are also known to be living in homes in Spain, Greece, Ukraine, Thailand and the Philippines.
Social Association of Germany, an advocacy group, said the numbers so far are an "alarm signal," given that Germany's population is both falling and aging.
"We simply cannot let those people who built Germany up to be what it is, who put their backbones into it all their lives, be deported," the group's president, Ulrike Mascher, told the British newspaper. "It is inhumane."
German long-term care facilities kept costs down in the past by employing workers from Eastern Europe, but costs have kept rising.