Tens of thousands of people marched in Dublin on Saturday to demand the loosening of some of the strictest abortion laws in the world ahead of a 2018 referendum on the issue.

Abortion remains a divisive issue in once stridently Catholic Ireland, where a complete ban on the procedure was only lifted in 2013 to allow terminations in cases where the mother's life was in danger.

In 2016 over 3,000 Irish women travelled to England for abortions, according to the British Department of Health, but activists say the real number is far higher.

The government has promised to hold a referendum next May or June, but it has yet to decide exactly what question to put to the Irish people.

The human rights arms of the United Nations and Council of Europe have pressed the government to decriminalise abortion and widen the law to allow for the procedure in cases of fatal foetal abnormality, rape or incest.

But pro-choice activists want a more liberal regime, closer to that of England, which allows terminations to be carried out up to 24 weeks after conception. Opinion polls show a large majority of voters want some change.

"Government ministers have suggested only the most restrictive terms will pass, but I think the people want more than that," said Sarah Murphy, a 26-year-old recruitment professional.

"Ireland is changing. I don't think you would have seen a march like this a few years ago," she said.

Like many at the march she was wearing a black jumper with the word Repeal in white, a reference to a campaign to repeal the eighth amendment of the Irish constitution, which gives the unborn child equal rights to those of the mother.

A panel of citizens called together to advise government on the issue voted overwhelmingly that the eighth amendment should be changed.

An all-party committee in parliament is now considering those recommendations and is due to report to parliament by the end of the year.

Some of the crowd, which marched across the city before assembling outside the office of Prime Minister Leo Varadkar, chanted "Get your rosaries off our ovaries" in reference to the influence the Catholic Church has long had on social policy in Ireland, while others held posters demanding "Repeal now."

The growing pro-choice movement is seen as a sign that the Catholic church, which has dominated Irish life for centuries, is continuing to lose influence.

Ireland was the first country to adopt gay marriage by popular vote in 2015, approving it by 62 percent to 38 percent despite the opposition of the church.