Ms Dati (right) has the full backing of President Sarkozy

The bill - which critics say will make prison overcrowding worse - is being introduced by Justice Minister Rachida Dati, who has recently come under fire.

A daughter of immigrants billed as an icon for multi-racial meritocracy, Ms Dati has been criticised in the media after several key aides resigned.

The row comes as her brother, convicted on drugs charges, is due back in court.

Ms Dati, 41, was appointed as justice minister in May, following the election of conservative President Nicholas Sarkozy.

She is the first person of North African origin to hold a senior cabinet post in France.

Her bill on tougher sentences for repeat offenders was called "potentially dangerous" by the opposition when it was debated in the Senate.

Critics say the measures will further add to already overcrowded prisons and only worsen repeat offending.

Disagreements?

Ms Dati also faces the spotlight over the resignations of her chief of staff and three of her advisers, who all stepped down in the past two weeks.

Officially they left for personal reasons or by mutual agreement, but there have been reports of disagreements with Ms Dati.

In all families, there are difficult moments, difficult stories, difficult stages Rachida Dati French justice minister Profile: Rachida Dati

"Is this unease due to Ms Dati's personality, [which is] apparently bossy and rather curt, or are there fundamental disagreements on policy and ongoing projects," an un-named trade union source told Le Monde newspaper.

"I think there is probably a bit of both."

Ms Dati has played down the significance of the resignations, telling French radio that they were part of the "daily life of cabinets".

Brother in trouble

Ms Dati's brother, Jamal Dati, is due to appear before an appeals court in Nancy, eastern France, on charges of drug dealing.

On the question of her brother, she said that "in all families, there are difficult moments, difficult stories, difficult stages", adding that she would make no further comments.

In February, Jamal Dati received a six-month suspended prison sentence and the obligation to seek treatment.

However, he told a regional newspaper on Tuesday that his troubles should not reflect on his sister.

"She is who she is, I am who I am," he said.

Ms Dati is one of 12 children born to a Moroccan mason father and an Algerian mother and raised in humble circumstances.

The premature death of her mother forced her to look after her younger sisters and brothers.

Jamal Dati's lawyer is quoted as saying that his client has struggled with difficulties over the death of his mother.

On Tuesday, the Speaker of France's National Assembly called for an end to the "unspeakable attacks" against Ms Dati.

"These attacks have the unbearable stench of jealousy and xenophobia," Bernard Accoyer told journalists.

Mr Sarkozy also defended Ms Dati at the weekend, and his wife, Cecilia Sarkozy, has spoken highly of their close relationship.