Concerns are growing in Japan over what critics describe as a dangerous drift toward suppressing anti-war voices in the name of national security, as the government pushes ahead with constitutional revisions and the creation of a new national intelligence structure.

Japan's House of Councillors on Wednesday passed legislation establishing a national intelligence council, as Prime Minister Sanae Takaichi moves to centralize and strengthen the country's intel capabilities. The bill had cleared the House of Representatives last month.

Under the legislation, Japan will build an intelligence system centered on the national intelligence council, with a national intelligence bureau serving as its operational arm.

Chaired by the prime minister, the council will comprise relevant Cabinet members, including the chief Cabinet secretary and foreign minister, while the bureau will coordinate intelligence work across government ministries and agencies.

Critics warn the move could pave the way for a broader expansion of executive power.