NAIROBI, Kenya (AP) _ President Daniel arap Moi ordered the release of four political prisoners Thursday and invited some dissidents in exile to return home, state radio reported.

The Voice of Kenya identified the four as Raila Odinga, son of former Vice President Oginga Odinga; lawyer Wanyiri Kihoro, former University of Nairobi lecturer David Mukaru Ng'ang'a, and Samuel Okumu Okwani.

Kihoro and Ng'ang'a sued the government in 1987, alleging torture. Their lawyer, Gibson Kamau Kuria, was arrested a day after he filed the suit and spent eight months in detention.

Kuria was awarded the 1988 Robert F. Kennedy Human Rights Award but declined to accept the cash prize until the government allows him to travel overseas.

Thursday's releases left seven political prisoners in Kenyan jails, according to government count. The detainees are held under the Preservation of Public Order and Security Act, which allows indefinite imprisonment without trial or charge.

''I have said those who have fled the country, not all, but those who have repented, can return home,'' Moi said at a rally. ''I am also going to look into the affairs of those in detention to see if they have reformed.''

Voice of Kenya made no mention if the releases were conditional, and the detainees could not be immediately contacted for comment.

The younger Odinga was detained for the second time in September and later identified in court as leader of the Kenya Revolutionary Front, until then an unknown group the government said was plotting Moi's overthrow.

Odinga had only had six months of freedom. He was first detained after a failed coup attempt in 1982 and was among 14 detaineed freed by a presidential pardon in February, 1988.

Kihoro and Mukaru were detained in 1986 during a crackdown of people suspected of links with Mwakenya, another clandestine group.

Okwani was detained in September after being mentioned in a trial of a Kenyan charged with travelling to Libya for guerrilla training to overthrow the government.

During the 1986 and 1987 crackdown against Mwakenya, the government arrested and jailed at least 100 people who confessed links with Mwakenya, Swahili language acronym for Organization for the Liberation of Kenya.

Human rights groups, including the London-based Amnesty International, claimed the confessions were coerced, a charge the government denied.

The government has never given a figure for dissidents in exile, but two former politicians and a university lecturer live in Europe, from where they criticize the pro-West and capitalist Kenya.

The three are former legislators Koigi wa Wamwere and Andrew Kimani Ngumba, who live in Norway and Sweden respectively. Ngugi wa Thion'go, novelist and playwright, lives in Britain. He formerly lectured in literature at the University of Nairobi.