The head priest of a prominent shrine in Tokyo was ambushed and killed with a samurai sword, apparently by her brother, who then took his own life, police in the Japanese capital have said.

A female accomplice also died in the attack and the priest's driver was injured, Tokyo Metropolitan Police said.

The motive was unclear, though Japanese media reported there may have been a feud between the priest and her brother.

Nagako Tomioka, the 58-year-old head of Tomioka Hachimangu shrine, was attacked as she got out of her car on Thursday night, police said.

Shigenaga Tomioka, 56, and an accomplice were hiding behind her house, they added.

Japanese media said he is the victim's brother, but police would not confirm that.

Japanese priests generally live on the grounds of their shrines or temples.

The accomplice attacked the driver with a samurai sword and pursued him as he ran out of the temple grounds and about 100 metres down a road, police said.

A trail of splattered blood was still visible on the pavement.

The driver's injuries were not life-threatening.

The brother is then believed to have killed the woman before committing suicide.

At least one blood-stained sword and two survival knives were found near the scene, Japanese media said.

The nearly 400-year-old Tomioka Hachimangu shrine is known for its close ties to sumo and holding one of Tokyo's three big Shinto festivals.