East German spies were legendary during the Cold War for the files they kept on both their own people and those from the West.

Now the last prime minister of East Germany wants to know what the West German spymasters were unearthing about during that time.

Now 90, Hans Modrow turned to Germany's top administrative court on Wednesday, arguing that, as an historian and writer, he needed to be able to peek at what the spymasters knew if he is to be able to properly tell stories about that era.

"How am I supposed to write it down properly if the western files about me remain sealed?" he asked the court.

Modrow was a long-time head of the Socialist Unity Party of East Germany and was elevated to the top political position of that country in November 1989, as East Germany fell into disarray and preparations were made for its merger with West Germany. He left office in April 1990.

The Federal Intelligence Service, the foreign intelligence of West Germany, which still operates in today's unified Germany, has admitted to keeping tabs on Modrow from 1958 to 1990. However, it has only released a few documents to him, citing a need to protect its sources.

German law gives individuals broad rights to see their own files, so long as they are more than 60 years old and seeing them would not endanger state security.

Modrow has been fighting for five years to see his files.

East Germany's secret files were laid bare after that country ceased to exist. Intelligence agents tore up most of the files in the country's waning days, out of concerns that those who had been watched would seek retaliation.

Crews remain at work trying to patch the damaged documents back together and interest in seeing surviving documents has been high since 1990 among those who were watched.

If the East German files have all been laid open, then the same should apply to those from West Germany, Modrow argues. German intelligence services say the West German documents are protected by existing law.