Protesters against the contentious secrecy law enacted exactly a year ago vowed Saturday to continue fighting to have it scrapped, amid concern the legislation will undermine the public's right to know.

With the law that toughens penalties for leakers of state secrets set to take effect Wednesday, about 1,600 people gathered in Tokyo's Hibiya Park before marching through the swanky Ginza district, while around 700 demonstrators took to the streets of Nagoya.

Lawyer Yuichi Kaido, an organizer of the Tokyo rally, said civic groups must remain vigilant as the secrecy law takes effect to ensure that activities at military bases and nuclear power plants can continue to be monitored.