France's upper house of parliament, the Senate, has voted overwhelmingly to enshrine women's right to abortion in the constitution.

The proposal, approved earlier by the lower house, the National Assembly, was backed by 267 votes to 50 on Wednesday.

Abortion has been legal in France since 1974 but pressure has grown to further cement it in law.

There is concern that the right to termination is being eroded in ally nations like the US and Poland.

French President Emmanuel Macron has called a special, repeat vote on Monday involving both houses meeting together away from Paris in the suburb of Versailles.

If the joint session approves the constitutional amendment with a majority of at least three-fifths, there will be no need to put it to a referendum.

An Ifop opinion poll taken in November 2022, when the National Assembly was voting on the legislation, suggested 86% of people supported the amendment.

None of the country's main political parties question the right to abortion but the language used in the amendment was revised after the 2022 vote, when the National Assembly endorsed the "right" to abortion.

Last month it voted again to back the "freedom" to have an abortion after Mr Macron's government called for Article 34 of the constitution to be amended to cite "the freedom of women to have recourse to an abortion, which is guaranteed".

This new wording on "guaranteed freedom" was approved by the Senate on Wednesday.

Posting on X, Mr Macron said he was committed to making women's freedom to resort to termination "irreversible" by inscribing it in the constitution.

Reacting to the vote, Justice Minister Éric Dupond-Moretti said his country was close to a "historic day" when it becomes "the first country in the world to protect in its constitution the freedom of women" to decide what happens to their bodies.

Speaking to AFP news agency, several conservative senators said they had felt under pressure to approve the amendment.

"If I vote against it, my daughters will no longer come for Christmas," said one woman, who asked to remain anonymous.

Debate over abortion has raged in the US since the Supreme Court there rescinded the nationwide right to a termination in June 2022.

As of last month, 21 of the country's 50 states have either total or partial abortion bans on the books, with some including harsh punishments for doctors and others who assist in accessing the procedure, including jail time, steep fines and the loss of medical licences.

Poland's Constitutional Court imposed a near-total ban on abortion in that country in 2020. It is now permitted only in cases of rape or incest or when pregnancy threatens a mother's health or life.