A national demonstration and rally will take place in Athlone, Co Westmeath, later today over the Mercosur free trade agreement.
European Union countries gave provisional clearance yesterday to the deal, the largest trade accord the EU has ever struck.
The event has been organised by Independent Ireland and will be attended by the Irish Farmers Association (IFA) and other agricultural groups.
At 11am, a convoy of tractors and other large vehicles is expected to travel west to east on the N6 between junction 12 and junction 10.
From there, farmers are expected to march to the Technological University of The Shannon, Midlands campus where a rally is due to get underway at around 1.30pm.
Independent Ireland said today was about "projecting a united front" in opposition to the Mercosur agreement, which it said is a bad deal for Irish farmers.
'This deal is not dead' - Mullooly
"Let me be very clear: this deal is not dead," said Independent Ireland MEP for the Midlands-North West Ciaran Mullooly.
"It has not been voted on in the EU Parliament. Nothing is done until MEPs vote in Strasbourg," he added.
Independent Ireland said it wants the event to be peaceful and has asked those who are attending to co-operate fully with gardaí.
Gardaí have warned motorists of significant traffic in Athlone this morning.
It is expected there will be additional traffic, including slow moving vehicles, on the N6, between junction 12 and junction 10 in the morning.
Gardaí have advised people travelling in the area to leave enough time for possible traffic disruptions and to expect some delays.
They said it is not intended that the N6 eastbound will be closed.
There will be additional traffic, parking and pedestrians in the vicinity of the N55 Cornamaddy roundabout, R916 and environs of TUS Athlone from early morning until the event finishes in the afternoon.
People visiting Athlone have been asked to be aware of potential traffic delays.
Gardaí said they will be liaising with Westmeath County Council and Transport Infrastructure Ireland to minimise disruption today.
Deal approved by EU member states
Ireland was one of five EU countries, including France, Austria, Hungary and Poland, to vote against the agreement with Argentina, Brazil, Paraguay and Uruguay, at a meeting in Brussels yesterday.
Twenty member states voted in favour, with Belgium abstaining, allowing for a qualified majority of at least 15 member states, representing at least 65% of the EU population.
The agreement must now be ratified by the European Parliament.
