A couple who allegedly murdered their two children with poisoned cannelloni have gone on trial in France.

Marie-Helene Martinez and husband Jean-Paul Steijns are accused of killing the youngsters with the laced pasta dish at their Marseille home in 2005.

It is alleged the couple believed they could better manage their debt without eight-year-old Melissa and seven-year-old Jason.

The parents also risked losing custody of the children to Martinez's first husband, who is their biological father.

Steijns has confessed to the murders — but Martinez maintains her innocence.

"I loved my children. I could never have done this," the mother told the court, fighting back tears.

The two face possible life sentences if they are found guilty.

French reports of the crime said the children went to bed without finishing their meals of meat-stuffed cannelloni on Sept. 18, 2005.

They died that night and their bodies were discovered in a car boot when Steijns confessed to police a month later.

But he told the Aix-en-Provence court his wife influenced him to commit the crime.

"I am conscious that I took part in a horrible act that claimed the lives of three innocent children," he said.

"I should have prevented her from committing such a crime.

"I died along with Melissa and Jason that night. There are no words to express what I am feeling."

Lawyers for the children's mother rejected the claims, telling the court Steijns was behind the murder plot and he was known as a con artist.

A verdict in the case is expected in less than a week.

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