Facebook has announced it is to stop accepting ads relating to the Irish abortion referendum that come from foreign-based advertisers.

It has made the decision, with immediate effect, after concerns were raised about organisations and individuals attempting to influence the campaign from outside Ireland.

The electorate is going to the polls on 25 May to decide whether or not it wants to repeal the eighth amendment of the constitution, which effectively bans abortion, and while the issue has sparked passions on both sides at home, it is also drawing much attention from abroad.

In a lengthy statement, Facebook explained the measures it had already taken to ensure transparency in this referendum campaign, including the “view ads” feature which it launched in Ireland on 25 April, so users could see where funding for an ad originated. Clearly, it now feels a need to take things further.

“We understand the sensitivity of this campaign and will be working hard to ensure neutrality at all stages. We are an open platform for people to express ideas and views on both sides of a debate. Our goal is simple: to help ensure a free, fair and transparent vote on this important issue,” Facebook said in a statement on Tuesday.

Repeal the Eighth: Ireland's abortion referendum explained

Facebook is under increased pressure around its role in elections, following the Cambridge Analytica scandal, and a widespread view that fake news was allowed to slip through the net in crucial recent polls such as the 2016 EU referendum, and the 2016 US presidential election.

With an issue as politically sensitive as abortion, it was widely expected Ireland would become a target for international pro-life and pro-choice groups, and that this could well be the first Irish election to be fought in earnest on social media.

Today’s move from the tech giant comes just under three weeks before the referendum day.

Currently the Yes side, which hopes to repeal the abortion ban, is maintaining the lead, but its core support has sunk below 50 per cent, and recent polls have shown gains made by the No campaign.