A French nursing assistant admitted today to suffocating eight of her newborn babies "because she did not want any more children", prosecutors said.

Dominique Cottrez, 45, was charged with murder after telling police that after having two daughters she did not want more nor "to see a doctor to get contraception", prosecutor Eric Vaillant told reporters.

Cottrez's husband Pierre-Marie Cottrez was freed after denying any knowledge of the killings, which came to light when police found skeletal remains buried in a garden and dumped in plastic sacks in a garage.

His wife, whose heavy build appears to have concealed the pregnancies from acquaintances, now faces trial and life imprisonment.

Investigators said she had confessed to suffocating the babies shortly after their births between 1989 and 2006 or 2007, and to concealing the bodies from her husband under household clutter in the garage.

The father told officers he had never suspected his wife was pregnant.

In past cases some defendants have said they were in denial about their pregnancies and not fully responsible for their actions, but Vaillant said Cottrez had admitted to being "perfectly aware" of her condition.

Stunned residents of the quiet village of Villers-au-Tertre in northern France put flowers and candles outside the two houses where police had found the infants' bodies over the previous few days.

Prosecutors described it as the worst case of infanticide in recent French history, following a string of similar cases in which isolated and troubled mothers disposed of their newborns.

The suspects were brought before a magistrate in the nearby town of Douai to hear the charges.

Pierre-Marie Cottrez worked as a carpenter and was a respected member of the village council in Villers-au-Tertre, a 620-strong community.

"He's on his third term in office. He used to volunteer in the community. He's a respectable man," local mayor Patrick Mercier told reporters.

Mercier said the councillor's wife was a more withdrawn person who rarely took part in village life. He said she had a weight problem which might be the reason why any pregnancies had passed unnoticed.

"No-one was aware of anything at all," said the shocked mayor.

The pair were arrested on Tuesday and questioned while police used sniffer dogs to search two addresses after the new owners of a home found the bones of two infants while digging to plant a tree in their garden.

The house previously belonged to the parents of the arrested woman.

According to Vaillant, the mother quickly confessed and told officers to search the couple's current home in another part of the village.

Teams went there and six more sets of remains were found in the garage, tied up in four plastic bin bags and concealed under plant pots and junk.

Gendarmes were deployed outside one of the houses where the bodies were found, and sealed off the entrance to the macabre scene with plastic sheeting.

"I'm very upset," said local priest Father Robert Meignotte. "I baptise five children every Sunday in the 17 villages of the parish. You don't just throw children out like that in a big bag. It's incomprehensible."

"I'm still in shock," said a former mayor of Villers-au-Tertre, Daniel Collignon, echoing the sentiments of many local people.

The couple had lived in the village for 15 years and had two grown-up daughters who have children themselves. Neither showed any sign of unusual behaviour, local residents said.

The incident follows a string of similar cases in France.

Earlier this year a mother was convicted of killing six of her newborn children and hiding them in the cellar of her house in northwestern France.

Another notorious recent case was of a mother who was jailed in June last year for smothering two boys born in secret at her expatriate home in South Korea, and a third child born in France, and hiding them in a freezer.