The Department of Foreign affairs has warned Irish people planning to visit Spain to be prepared to adjust their travel plans at short notice if necessary.
It comes after The Spanish government has sacked Catalonia's cabinet after the region voted for independence from Madrid.
Spain's prime minister, Mariano Rajoy, said he is calling for a new regional election on December 21.
The department says there have been some incidents of violence, with travellers urged to avoid confrontation with police or demonstrators.
The travel advice says there is a possibility of further spontaneous gatherings and protests in Catalonia and elsewhere in Spain, which could have the potential to affect local transport and other services.
They said: "The political situation in Spain is reasonably stable but there has been an increase in industrial actions and public demonstrations, which can affect local services or public transport and disrupt traffic, particularly in major cities such as Madrid and Barcelona.
"We recommend that you stay clear of demonstrations and avoid confrontation with police or demonstrators. When a demonstration is planned or in progress, avoid the routes marchers plan to take."