TOKYO (Reuters) - Japanese Prime Minister Shinzo Abe’s ruling bloc pushed a bill targeting conspiracies to commit terrorism and other serious crimes through parliament’s lower house on Tuesday, despite fears the changes could allow police to trample civil liberties.

Protesters shout slogans as they protest against an anti-conspiracy bill outside parlliament building in Tokyo, Japan May 23, 2017. REUTERS/Issei Kato

The lower house vote, held despite opposition party protests and concern raised by a U.N. expert, sets the stage for enactment after approval by the upper house, where the ruling coalition also has a majority.

Japanese governments have tried three times without success to pass similar legislation, which officials say is needed to ratify a U.N. treaty aimed at global organized crime as well as to prevent terrorism as Tokyo prepares to host the 2020 Olympics.

Speaking after what British police believe was a terrorist attack in Manchester on Monday in which at least 22 people died, Chief Cabinet Secretary Yoshihide Suga stressed the need for the changes to facilitate coordination with other countries.

“We would like the legislation enacted as soon as possible,” Suga said.

Opponents, however, see the legislation of part of a broader agenda by Abe to increase state powers.

“Abe and the LDP (the ruling Liberal Democratic Party) want to dramatically change the balance between protecting individual rights and police powers,” said Lawrence Repeta, an expert on Japan’s legal system.

Despite government assurances to the contrary, opponents fear ordinary citizens could be targeted. Critics say that combined with a widening of legal wiretapping and the reluctance of courts to limit police surveillance powers, the changes could deter grassroots opposition to government policies.

Hundreds of mostly elderly protesters gathered outside parliament to voice their opposition.

“This law would enable security police to strengthen surveillance,” said retired Michiko Mori, 76.

“If you are more likely to be monitored and arrested, you would shrink from citizens’ movements.”

The legislation would criminalize plotting and preparing to commit 277 “serious crimes” that critics such as the Japan Federation of Bar Associations note include acts with no obvious connection to terrorism or organized crime, such as sit-ins to protest construction of apartment buildings or copying music.

Critics also say gathering information on possible plots would require expanded police surveillance, prompting comparisons with Japan’s prewar thought police.

“We must not allow the creation of a surveillance society,” the lawyers group said in a statement.

Last week, the U.N. special rapporteur on the right to privacy, Joseph Cannataci, wrote to Abe asking him to address the risk that the changes could “lead to undue restrictions to the rights to privacy and to freedom of expression”.

Suga lashed back on Monday, calling the letter “clearly inappropriate” and adding Tokyo had protested. Cannataci responded by calling Suga’s remarks “angry words” with “no substance” in an email to Reuters.

A Kyodo news agency survey published on Sunday showed voters are split over the bill, with support at 39.9 percent and opposition at 41.4 percent.