PHNOM PENH, Cambodia (AP) _ From inside Phnom Penh's decrepit French colonial-era prison, Khan Yourn waits for a royal amnesty that would free her and hundreds of other inmates.

King Norodom Sihanouk called two months ago for a general amnesty for all Cambodia's prisoners to morally balance his pardon of a notorious Khmer Rouge leader. But a tangled political struggle between the king and one of the country's two prime ministers has dashed prisoners' hope it will materialize.

Many of those who would have been freed were convicted of serious crimes _ 26-year-old Khan Yourn is accused of killing her infant daughter, whom she says died accidentally. Still, human rights activists praised the plan because Cambodia's prisons are overcrowded, unsanitary and often dangerous.

Only those deemed the most dangerous of the 2,500 inmates in 22 jails were to be exempt.

In calling for the amnesty, the king said no ordinary prisoner should be punished when Ieng Sary, the guerrilla leader he was compelled to pardon to advance peace negotiations, was allowed to walk free.

``Whatever wrongs or crimes committed by these prisoners, no one can pretend that they were as serious as those committed by the Khmer Rouge,'' the king said, referring to the genocide of 2 million Cambodians from 1975 to 1979 under Khmer Rouge rule.

Sary led the Khmer Rouge split in August that resulted in thousands of guerrillas defecting to the government. A dwindling number of hard-liners remain loyal to Sary's infamous brother-in-law, Pol Pot. Sary's price for making peace was a royal amnesty.

The king, empowered by the constitution to grant amnesty, was believed to have another motive for declaring a general amnesty _ to allow his half-brother Prince Norodom Sirivudh to return from exile in France without fear of prison. That has led to a tug-of-war with Second Prime Minister Hun Sen, who wields much of the actual political power in Cambodia.

Sirivudh, the former secretary general of the royalist party FUNCINPEC, was exiled a year ago after Hun Sen accused him of plotting his assassination. Sirivudh denied the charges.

The prince was sentenced in absentia to 10 years in prison in a trial independent observers labeled a travesty.

A group of university students, with Hun Sen's apparent blessing, protested the mass amnesty and the return of Prince Sirivudh.

Bowing to pressure, Sihanouk withdrew plans for a general amnesty and presented a specific list of 260 inmates to Justice Minister Chem Sngoun _ a member of Hun Sen's party _ in late November.

It comprised mostly women, children, the seriously sick and elderly as well as some accused of involvement with the outlawed Khmer Rouge.

Chem Sngoun rejected the list, citing a 1988 law setting guidelines for prisoner amnesties. He also spurned the trimmed list of 144 names that followed.

The dispute underscores Sihanouk's increasing powerlessness, because he technically has an unlimited constitutional right to grant amnesty that requires no approval from the justice ministry.

Hun Sen, who led a Vietnam-backed single-party government in the 1980s, retains control over most of the security apparatus. His party also has the most widespread presence in the provinces, which could be a key factor in elections due in 1998.

Human rights groups have criticized the delay in the amnesty, saying seriously ill prisoners or those with children should be released.

Thomas Hammarberg, special representative of the United Nations Secretary-General for Human Rights in Cambodia, said inadequate food has contributed to malnutrition and the spread of disease.