Facebook has agreed to publish data on political advertising during the abortion referendum campaign.
The social media company will share details of pages associated with campaign groups and the amount they spent on ads.
Facebook will also reveal how many ads it blocked after introducing a ban on foreign organisations paying for ads.
Green Party leader Eamonn Ryan says the company wrote to him after he had been campaigning for Transparency since the abortion referendum.
He says it sets an international precedent: 'We need to know what happened online during the referendum campaign, half way through it Facebook and then google pulled foreign adverts, and then all adverts in Google's case, and we want to know was that because there was a wall of money coming in, or was it similar to what happened in the Brexit referendum or the Trump election where there was a huge amount of foreign money trying to effect a campaign'.