After posting about Fay Weldons book, I thought it would be good to explore what a Kehua is in Maori culture. I cam across this interesting article from the Transaction and Proceedings of the Royal Society of New Zealand 1868- 1961
Chapter 37 1904 by Eldson Best
When a Maori dies, the wairua, or dream-ghost, or soul, which during life could leave the body and wander at large when its owner slept, becomes a kehua. “Kehua,” says Best, “are the spirits of the dead which revisit their former haunts of this world and make things unpleasant for the living. Kehua appear to return to earth generally during the night-time—they dread sunlight and the light of fires. Some say the wairua, or ghost of a dead person, remains here as a kehua or atua whakahaehae until the body is buried; it then descends to Hades.”
Kehua are said by some to be invisible, and capable of acting benevolently or in a hostile manner upon men. They can communicate with mortals; they eat and drink, wander about the village; they can see and hear what is going on about them. In fact, these disembodied spirits retain many of the characteristics of their living fellow-men.
Ghosts of the dead are invisible except to people who are asleep, or to priests in a state of trance. Tohungas, who possess clairvoyant powers (matakite or matatuhi), sometimes saw a whole host of ghosts of the dead (kehua) traversing space. Such a company was termed a tira māka or kahui atua, and the object of their visiting this world was to acquaint living persons with the fact that some disaster or death was imminent. Tohungas would drive them away to avert the evil. It was a common thing for spirits of the dead to appear to their living relatives in order to warn them of evil. Should a person dream that he is chased by the ghost of a dead person, and the kehua from the Po (Hades) catches him, that is an evil omen; he may soon take ill and die. When a kehua appears to the wairua (dream-ghost) of a living person it is anthropomorphic, but when it appears at the request of its medium—say, at a spiritualistic seance—it assumes the form of a spider or lizard, &c. It can also make its appearance as a shadow of a sun-ray. Ghosts of the dead were said to have returned to this world in the form of butterflies. In Samoa they are said to return in the form of moths. The Maori ghost, like the Australian, often revisits the spot where his bones are deposited. “Sometimes,” said Beviuk, a New South Wales black, “the murup comes back to this world and looks down into his grave, and may say, ‘Hallo, there is my old’ possum rug; there are my old bones.’ “If a Maori trespassed on a burial-ground the ghosts of those interred there would punish him with disease, and perhaps death. Their presence is said to be made known generally by a whistling sound. A breath of warm air felt while travelling at night is a sign of the near presence of a kehua.
Irirangi is the term applied to a spirit-voice heard singing without, when at night the people are within their houses: it is an omen of evil import. Shortland says the voice of ancestral ghosts is not like that of mortals, but a kind of sound—half whistle, half whisper. He had a conference with the ghosts of two chiefs who had been several years dead, and was assured that such was always the peculiar voice of atua when they talk with man. Other Europeans have had similar intercourse with Maori ghosts, and one need hardly explain that the mysterious voice was in every case the ventriloquistic utterance of the spirit’s medium. I have already pointed out that the kehua become hungry like ordinary mortals, and Taylor states that they were thought to feed on flies and filth; but they also had the spirit of the kumara and taro (?).
When a Maori dies his wairua (soul) leaves the body, and either remains near the corpse or goes away to the lower world. In either case it can return, and, re-entering the corpse, bring it to life again. If the kehua goes to the nether regions it may be sent back to this world by its relatives, for the purpose of caring for its children who have been left without a guardian owing to the parents’ death, but no soul can return to earth if in Hades it eats of the food of the denizens of that region.
The tohungas have elaborate ceremonies by means of which they restore the soul to a person just dead, but the feat is rarely performed, because the necessary astrological juxtapositions are rare favourable. The ancient Greeks offered the ghost fresh blood, that it might for a time be called back into life and answer questions—a conception which gave birth to the practice of raising the dead and asking oracles of them. By performing the hirihiri divination rite over a corpse the Maoris were enabled to consult the kehua or wairua of the dead person, and gain information as to the cause of its death. I have already referred to the hosts of ancestral ghosts sometimes seen by the matakite or clairvoyant seer: these companies of spirits were called apa hau by the Tuhoe people, and they were represented in the living world by some living relative, who was the medium (kauwaka or kaupapa) through which such spirits communicated with, and acted as guardians of, their living relatives. A single person may be the medium of the kehua of many deceased relatives. Such kehua or wairua do not abide with the medium, but visit him when they have anything to communicate. The medium may be quite a common person, of no standing in the tribe until he becomes a medium.
That is only a small excerpt, read the whole article here on the National Library of New Zealand website.