A seven-year-old boy missing since his parents abandoned him in a bear-inhabited forest in northern Japan as a punishment nearly a week ago was found alive on Friday, officials said.

The boy, apparently unharmed and in good health, was discovered inside a military base at about 7:50 am (2250 GMT Thursday), a police spokesman said.

"A Self-Defence Force official who was on a drill found a boy whose age appeared to be seven," he told AFP.

"There was no conspicuous external injury, and the boy introduced himself as Yamato Tanooka," said the spokesman for police in northern Hokkaido island.

Manabu Takehara, a spokesman for the Self-Defense Forces, also confirmed that the boy was found.

"He looked in good health, but he was sent to hospital by medical helicopter" for a check-up, he told AFP.

The child had been missing since Saturday after his parents said they made him get out of their car on a mountain road as punishment for misbehaving.

He was reportedly without food or water.

The parents originally told police their son had got lost while they were out hiking to gather wild vegetables, but later admitted they became angry and ordered him onto the road because he had thrown stones at cars and people.

The local Hokkaido Shimbun newspaper reported that the boy told police that on Saturday night he had walked to a hut inside the military base and taken shelter there.

The base is reportedly located some 5.5 kilometres (3.4 miles) northeast of the site where the child went missing.

Japanese media interrupted regular programmes to broadcast news of the stunning development in the case which has drawn huge media attention -- and criticism of the parents' actions.

Police rescuers and fire personnel initially led the search for the boy but after coming up empty-handed the local town of Nanae requested military support.

From Wednesday Japanese soldiers joined in the hunt in the rugged region, where heavy rains at times hampered the operation conducted in overgrown forest and through tall bushes.

Searchers had expressed frustration that they were unable to find any evidence of the boy's whereabouts.

Police have said they are considering filing neglect charges against his parents, according to Kyodo News.

"I feel very sorry for my child," the father told a television reporter earlier this week, as Japanese public opinion bubbled with outrage over the parents' actions.

"I am so sorry for causing trouble for many people."