A bill aimed at penalizing Internet users for downloading pirated music and video files passed the Diet on Wednesday, despite criticism from some Internet personalities and legal experts that the move is hasty and too harsh.

The revision to the Copyright Law cleared the Education, Culture and Science Committee of the House of Councilors on Wednesday morning and was then approved by a 221-12 vote in an Upper House plenary session that afternoon. The bill makes downloading of such pirated content punishable by a maximum of two years in prison and/or a fine of up to ¥2 million. A 2010 revision to the same law made the downloading of such contents illegal, but avoided assigning penalties.

The uploading of pirated music and video content has long been illegal and carries a maximum 10 years in prison or a fine of up to ¥10 million.

The bill was originally submitted by the education ministry earlier this year, but it did not include provisions on penalties. A group of lawmakers from the opposition Liberal Democratic Party and New Komeito then proposed inserting the penalty clause by submitting an amendment to the bill. The revised bill cleared the House of Representatives and was sent to the House of Councilors on Friday. The penalty clause will go into effect on Oct. 1.

The nation's music industry has long lobbied for tougher action on piracy, saying the acts have cost copyright holders a fortune. The Recording Industry Association of Japan estimates 4.36 billion pirated music files were downloaded in 2010, amounting to ¥668.3 billion in lost revenue for the industry.

In the Upper House committee meeting on Tuesday, however, DPJ member Yuko Mori said it's difficult for ordinary users to tell which files are illegal and that the bill's vague wording of punishing "those who are aware (of the illegality of downloading)" could lead to arbitrary prosecution. "We shouldn't risk making the general public — including youths — the subject of criminal investigations," she said.

Daisuke Tsuda, an IT and music journalist called in as an expert witness, also expressed fears that the prosecution of pirated music could eventually be extended to other materials such as games and writings, hampering the public's access to information and the long-term promotion of contents industries. He added that the government should think of ways to better clamp down on uploaders, not downloaders.

"There won't be illegal downloading without illegal uploading," he said. "What's important is to turn off the tap. ... There are many ways to improve the ways we clamp down on piracy. So why are we turning to such a violent method?"