A 28-year-old woman in Germany killed her five babies shortly after giving birth in secret at home and in the woods, and hid their bodies, officials say.

She was worried her husband would leave her if she had any more children.

The woman, who has been arrested on five counts of manslaughter, made a "comprehensive confession" to the killings after turning herself in as a six-year investigation closed in on her, said Ulrike Stahlmann-Liebelt, the head prosecutor in Flensburg, on Germany's border with Denmark.

Ms Stahlmann-Liebelt said the woman, whose name was not released, has two living children, aged eight and 10. But then in 2006 she began hiding her pregnancies, staying away from doctors and hospitals and killing the infants after giving birth to two at home and three in the woods, she said.

"She had the impression her husband would leave her if she had any more children, and that's why she didn't tell anyone she was pregnant, including her husband.

"She has said that the family lived at a certain level of prosperity, that it was clear her husband did not want any more children, and that one reason was to preserve this standard, and she feared that might be endangered if another child were there."

The husband has told police that he knew nothing about the pregnancies, and it was not entirely clear how the woman managed to keep them secret.

Police found the first infant's body dumped in a paper sorting station in 2006 about 15 kilometresaway from the town of Husum where the woman lived. The second was found in a parking area off a regional main road.

After reading news reports that DNA results had confirmed the two children had the same parents, the woman then decided not to dispose of the other bodies in public places.

She hid the next three infants in boxes in the basement of the building where she lived.

The bodies have now been recovered and post mortems have been carried out, but forensic experts have not yet been able to determine the cause or dates of their death.

Germany has Europe's most widespread network of so-called baby-boxes - hatches usually run by church groups and charities and associated with hospitals where people can give up their newborns entirely anonymously and safely - but Stahlmann-Liebelt said the woman told authorities she did not know how to go about finding one.

After finding the first two babies, authorities were able to narrow down the likelihood that the parents came from the area around Husum, a town on the North Sea coast.

They took hundreds of DNA tests from women in the area over time and took a sample from the woman on Tuesday.

A short time after - before the sample had been processed - the woman turned herself in and confessed.

Police official Dirk Czarnetzkisaid the woman's decision to submit to a saliva test and to make a long statement to police suggested "that she felt relieved of great pressure ... simply to be able to say it."

"It's important to stress that, as things stand, our assessment is that no one else was involved and it is apparently the case - incredible as it might seem - that no one noticed the pregnancies or the birth of these children," he said.

A judge has ordered the woman held in custody pending a formal charge, which typically takes several months.