Saiful Mulook told a news conference in Frankfurt that Bibi was now free but she and her family needed a passport to leave the country.
Bibi, 53, was convicted of blasphemy in 2010 over allegations she made derogatory remarks about Islam after neighbours objected to her drinking water from their glass because she was not Muslim.
The Supreme Court acquitted her last month.
It was unclear why citizenship, rather than a visa, was necessary for her to leave Pakistan, though Mulook said pressure from religious extremists was making it harder for Islamabad to arrange her departure.
She and her family are staying at a safe house in Pakistan, despite offers of asylum from countries including Canada.
Mulook said the status of a friend of Bibi's husband, who has a wife and five daughters, whom he would like to join them, was a sticking point. Another wife of Bibi's husband and her three daughters were not seeking to leave Pakistan with Bibi, he added.
German officials have said that they and a number of other countries are in talks with Bibi's family and the Pakistani government to find a way of rehousing her.
Mulook, who has himself sought refuge in the Netherlands after being threatened for taking on Bibi's case, said Bibi had no preference as to which country she would travel to for asylum.
The German government had no immediate comment on the request for a passport.
Bibi, 53, was convicted of blasphemy in 2010 over allegations she made derogatory remarks about Islam after neighbours objected to her drinking water from their glass because she was not Muslim. Pakistan's Supreme Court acquitted her last month.