He is attending a Digital Summit in the Estonian capital
The Taoiseach Leo Varadkar has said he intends to push for a good deal for Irish beef farmers in South America.
He is attending a Digital Summit with EU leaders in the Estonian capital of Tallinn.
The gathering is focused on essential topics in relation to digital issues for Europe - such as security, e-government, industry, society and the economy.
But the meeting will also see informal meetings mixed with the official agenda.
Mr Varadkar says he will take the opportunity to raise the issue of Brexit and Mercosur.
The EU is currently negotiating a free trade agreement with Argentina, Brazil, Paraguay, and Uruguay - known as Mercosur.
Venezuela has been a member of Mercosur since 2012 but is an observer in the negotiations, not a party.
The current negotiations cover a range of issues including:
The Irish Farmers Association (IFA) has outlined strong opposition to any offer on beef which would increase access in the trade negotiations.
IFA President Joe Healy said with Brexit uncertainty and the Brazilian meat scandal, now is not the time to make "concessions" to South America.
The association says there can be no increase in import volumes or additional tariff rate quotas in any new offer in Mercosur.
"The EU cannot make any new offer which will damage the EU beef sector by allowing the South Americans to cherry pick the high price EU steak market", it says.
"EU beef consumption is down over 20% in the last decade. Concessions in Mercosur will have a devastating impact on farmers, our quality suckler cow herd and lead to job losses in rural areas," it adds.
In a video message from the Government Jet, Mr Varadkar said: "I'm going to try to take the opportunity to speak with President Juncker about Mercosur.
"I'm very much in favour of it because free trade makes everyone better off - creates jobs and create revenues - but there's a particular concern for our Irish beef sector.
"And I want to make sure that we insist really on the highest standards of animal welfare and also health and safety - and also make sure that our beef farmers are competing on a level playing field.
"Because fair trade is as important as free trade".