The undated video - probably recorded under duress by his captors - was broadcast Saturday by Pakistan's Dunya TV. The German Foreign Ministry in Berlin said it "knows the case" and is aware of the video. A duty spokeswoman declined to elaborate.
Aid organization German Agro Action declined to confirm whether the video indeed showed one of its two staffers abducted in the central Pakistan city of Multan in January. Spokeswoman Simone Pott only acknowledged "we know the video."
The aid worker, identifying himself in the video as 59-year-old Bernd Muehlenbeck, said he was captured by mujahedeen - a generic term for militant Islamic extremists - but didn't specify who they were or what their demands were.
In the message - whose content is likely to have been dictated by the captors - he said he was kidnapped "by mujahedeen because of the bad policies of the German government."
In January, gunmen seized the two foreign aid workers, Muehlenbeck and an Italian colleague, from just outside their office in Multan and bundled them into a car, according to Pakistan security officials. The men were working for a development project helping victims of the 2010 floods, the officials said.
Muehlenbeck did not name or explicitly mention his Italian colleague, but repeatedly used the plural when speaking about his situation.
He appealed to authorities not to attempt freeing them by force. "I would like to live and I would like to see back my family alive," he said, speaking in English with a slight German accent.
In the video lasting just less than a minute, Muehlenbeck is heard speaking calmly in front of a white wall, wearing glasses and a dark hoody.
He said he could be killed by his captors at any time. "We don't know when. Maybe today, maybe tomorrow, maybe in three days."
Pakistan, a poor predominantly Muslim nation of about 180 million, is struggling to fend off an insurgency fueled by Islamic extremists, many of whom are believed to hide in the lawless provinces bordering Afghanistan.
Kidnappings for ransom are common in Pakistan. Islamist militants have also abducted people. Several aid workers have been targeted over the past years.
This week saw a gruesome series of deadly attacks on Pakistanis working on a polio vaccination campaign. Six of the aid workers gunned down were women, three of whom were teenagers. Two other workers were critically wounded.
(Copyright 2012 by The Associated Press. All Rights Reserved.)