The Taoiseach Micheál Martin will travel to Madrid on Wednesday to attend a dinner hosted by Spanish Prime Minister Pedro Sánchez.
The EuroAtlantic event will be attended by all EU and NATO leaders, and will take place on the margins of a NATO summit in the Spanish capital.
While in Madrid, Mr Martin will have a number of bilateral meetings - including with the leaders of Norway, Iceland and Austria.
He will also attend an Irish-Spanish business event.
Speaking in advance of his visit, the Taoiseach said: "I look forward to engaging with a number of other leaders in Madrid.
"Russia's military aggression against Ukraine has highlighted more than ever the importance of solidarity and cooperation between like-minded partners.
"In particular, it is a keen reminder of the absolute necessity of upholding a rules-based international order, and the dire consequences for all of us when that order is undermined.
"As our societies face complex and unpredictable threats aimed at destabilising the foundations of our democracies, it makes sense to bolster international cooperation to work to uphold democratic values and our commitment to that rules-based international order."
NATO membership
It comes as Turkey, Sweden and Finland have signed a memorandum for the two Nordic states to join NATO, removing a Turkish block to the accession process.
A statement from the president of Finland, Sauli Niinisto, said: "We had a thorough meeting with president of Turkey Recep Tayyip Erdogan and Prime Minister of Sweden Magdalena Andersson, facilitated by Secretary-General of NATO Jens Stoltenberg.
"As a result of that meeting, our foreign ministers signed a trilateral memorandum which confirms that Turkey will at the Madrid summit this week support the invitation of Finland and Sweden to become members of NATO."
NATO chief Stoltenberg said: "I am pleased to announce that we now have an agreement that paves the way for Finland and Sweden to join NATO.
"Turkey, Finland and Sweden have signed a memorandum that addresses Turkey's concerns, including around arms exports and the fight against terrorism."
A statement from Finland said: "Our joint memorandum underscores the commitment of Finland, Sweden and Turkey to extend their full support against threats to each other's security. Us becoming NATO allies will further strengthen this commitment.
"Over the past weeks, Turkey has raised its concerns over the threat of terrorism. Finland has constantly taken these concerns seriously.
"Finland condemns terrorism in all its forms and manifestations. As a NATO member, Finland will commit fully to the counterterrorism documents and policies of NATO."
The traditionally neutral countries decided to apply for NATO membership following the Russian invasion of Ukraine.
Additional reporting: IRN
