The company says its new 'view ads' feature is live from Tuesday
Social media site Facebook says it is no longer accepting adverts related to the Eighth Amendment referendum if they are based outside of Ireland.
The company says concerns have been raised about organisations and individuals based outside the country trying to influence the outcome of the referendum by buying ads on Facebook.
In a post, Facebook says: "This is an issue we have been thinking about for some time.
"Today, as part of our efforts to help protect the integrity of elections and referendums from undue influence, we will begin rejecting ads related to the referendum if they are being run by advertisers based outside of Ireland.
"Our company approach is to build tools to increase transparency around political advertising so that people know who is paying for the ads they are seeing, and to ensure any organisation running a political ad is located in that country.
"We have already begun to roll out the first of our ads transparency tools in Ireland.
"Our view ads feature - which enables Irish Facebook users to see all of the ads any advertiser is running on Facebook in Ireland at the same time - has been fast tracked and is operational today."
Additional election integrity tools being built include a verification process that requires the advertiser to be resident in the country where the election is taking place.
Facebook explains: "This change will apply to ads we determine to be coming from foreign entities which are attempting to influence the outcome of the vote on May 25th.
"We do not intend to block campaigns and advocacy organisations in Ireland from using service providers outside of Ireland."
Green Party leader Eamon Ryan welcomed the announcement: "The referendum on May 25th is a decision for the Irish people - not for international interests.
"We have strong rules on campaign finance and on traditional advertising, but they are not fit for purpose when it comes to digital advertising, especially from outside the jurisdiction.
"Ireland needs to modernise its laws in this regard, but in the short term, this move is an immediate improvement from Facebook to tackle concerns the Irish people have on foreign influence in this referendum."
The party is also calling on Google to introduce similar restrictions on its YouTube platform.
Together For Yes, the umbrella group of civil society organisations calling for a Yes vote, also welcomed Facebook's announcement.
Campaign Co-Director Ailbhe Smyth said: "Facebook is the modern-day billboard, and until today, external campaigners had free rein to interfere with and manipulate the conversation Ireland is having around removing the 8th amendment from our Constitution.
“We view this as a clear recognition by Facebook that external forces with vast resources can have disproportionate yet impactful influence in political campaigns. Today’s announcement means the integrity of Ireland’s democratic process will be protected to some extent, and this is therefore a significant step."
She added: “Together For Yes previously voiced our strong concerns about Trump and Brexit-style social media tactics being used in the referendum, and urged people to be vigilant of biased information masquerading as neutral sources. "