A pre-trial hearing for the man accused of killing Japan's former prime minister Shinzo Abe was cancelled Monday after a suspicious object was delivered to the court, local media said.

Nara District Court could not immediately confirm the reports by public broadcaster NHK and other outlets, which said the site was evacuated after what appeared to be an "unidentified bag" arrived at the court.

Tetsuya Yamagami had been due to appear on Monday afternoon for a pre-trial hearing over Abe's broad-daylight assassination which shocked the world in July last year.

The 42-year-old faces charges of murder and violation of arms control laws, and could face the death penalty if convicted.

He reportedly targeted Abe over the former leader's ties to the Unification Church, the global sect whose members are sometimes referred to as "Moonies".

Yamagami is believed to have resented the church over large donations his mother made that bankrupted his family.

Abe, Japan's best known politician and longest-serving prime minister, was shot with an apparently homemade gun while speaking at a campaign event on July 8.

The circumstances of the assassination have ignited scrutiny of what authorities admitted were security "shortcomings", and led to the resignation of Japan's police chief.

Yamagami, who underwent a psychiatric assessment which ended in January, spent three years in the navy following a childhood reportedly marred by his father's suicide and his mother's alleged neglect and devotion to church activities.

Details of his upbringing have stoked anger against the Unification Church and garnered Yamagami sympathy -- with supporters showing support for him through donations and a petition calling for leniency.

The Unification Church is a global religious movement founded in Korea in the 1950s by self-styled messiah Sun Myung Moon.

In a letter published by Japanese media, Yamagami accused Abe of supporting the church and expressed resentment towards the group.

The church has confirmed his mother's membership but refused to specify the amount of donations she made, which reports said may have totalled around 100 million yen ($700,000).

Less than a year after Abe's death, in April, a man hurled an explosive device towards Prime Minister Fumio Kishida shortly before he was due to deliver a campaign speech in the city of Wakayama.

The leader escaped unharmed, but the fact that an assailant was able to throw the device at such close range so soon after the Abe murder prompted renewed criticism of security arrangements in Japan.