A woman is on trial in France accused of suffocating eight of her newborn babies because she feared they were children she had with her father.

Dominique Cottrez (51) told investigators she was raped by him, first when she was eight and then repeatedly through her childhood and teenage years.

She said she later had a long, incestuous relationship with him when she was an adult, including after she married, and said it became consensual.

She said she was in love with him more than she was with her husband Pierre-Marie Cottrez.

Dominique Cottrez, who is accused of multiple counts of first-degree murder of minors, told the investigating judge she had never used contraception or had an abortion because she had a phobia of doctors.

She said the killings in the northern village of Villers-au-Tertre had become a "means of contraception," according to the judicial documents, in the worst infanticide case in modern French history.

Ms Cottrez, who has two grown-up daughters, told investigators that for more than a decade, she carried several babies to term and then killed them.

Her obesity appeared to hide the pregnancies, which went unnoticed by her husband, children, neighbours, colleagues and even hospital doctors.

A man who found the first corpse was one of the first witnesses to take the stand at the court in the northern city of Douai.

Leonard Meriaux made the gruesome discovery in 2010 in the garden of the Cottrez family house after he had bought the property.

He called police, who found another in the garden and six more in the garage of the house.

Investigators questioned Cottrez, who allegedly confessed. She faces life in prison if found guilty by a jury.

Dozens of forensic and psychiatric experts, police investigators and witnesses, including her husband, daughters and siblings, are scheduled to give evidence in the trial.

Cottrez's father died in 2007.