Thousands of people marched in Dublin on Saturday calling for an overhaul of Ireland's strict abortion laws, as a campaign for change gathers momentum ahead of the upcoming general election.

Ireland has some of Europe's most restrictive abortion laws. Termination is allowed only when there is risk to the life of the mother, rather than just her health.

Campaigners and politicians are calling for a referendum to be held to repeal the eighth amendment of the constitution, which grants equal rights to the foetus and the mother.

"We want to sell a really strong, confident message to the government that it's not enough to kick the issue down the road anymore," said organiser Cathleen Doherty of the Abortion Rights Campaign.

"We want to see a pledge to repeal the eighth in their manifestos for the election," she told AFP.

Irish police declined to give an estimate on the crowd but organisers were expecting 8,000 to 10,000 people.

Demonstrators chanted: "What do we want? The right to choose. When do we want it? Now."

Abortion is a deeply divisive issue in Ireland, a traditionally Roman Catholic country, and ignites fierce debate whenever it is raised in public.

May's referendum on introducing same-sex marriage, passed by a resounding "Yes" vote, has added to the momentum for broader social change.