TOKYO (Reuters) - A Japanese man died after setting himself on fire in a downtown Tokyo park in an apparent protest against the country's shift away from postwar pacifism under Prime Minister Shinzo Abe, NHK national television said on Wednesday.

Abe's cabinet in July freed up constraints that had kept the military from fighting abroad, in a major political victory, although one widely opposed by voters.

Media say Abe could postpone a planned tax increase and call a general election for December, which some political insiders view as a way to lock in his mandate for the defense legislation and other unpopular measures.

Police responding to an emergency call on Tuesday night found the man on fire in Hibiya Park, which is near parliament and government offices. He was pronounced dead soon after being taken to hospital.

A video camera recording was found nearby, along with a letter to Abe and the heads of both houses of parliament protesting the easing of the curbs on the military, NHK said.

Police would not confirm the report of the incident.

In June, a man set himself on fire at a busy Tokyo intersection in front of hundreds of bystanders to protest impending approval of the change.

Legislation still needs to be passed to enable the defense changes, against which thousands protested. They are among several unpopular issues Abe confronts next year in the face of declining support.

(Reporting by Elaine Lies; Editing by Clarence Fernandez)