Japan's main opposition party has criticized the government's interpretation of "political neutrality" in the Broadcasting Act as being ambiguous, and has called on the government to retract part of it.

The demand comes after a member of the Constitutional Democratic Party earlier obtained internal documents from the communications ministry showing the interpretation of the law. The ministry later admitted the leaked papers were official documents.

In the documents, the government presented a unified view in 2016 that it would evaluate broadcasters based on their entire programming to determine whether they are politically biased. But the government also said the broadcasters' political impartiality could not be confirmed if a single program were to clearly deviate from neutrality.

The party's Diet affairs chief Azumi Jun said on Sunday that although the government said it had not changed its interpretation, it "threatened" to disband broadcasters for making a single program it deemed to be politically biased.

He described such a view as ambiguous, and called on the government to retract the part about the single program if its stance remains unchanged as it had stated.

Azumi also demanded the communications ministry clarify by Monday whether the contents of its documents are true.