Questions are being raised about a visit by Taoiseach Leo Varadkar with the Hungarian Prime Minister Viktor Orbán.
Mr Varadkar and Minister of State for European Affairs Helen McEntee are travelling to Budapest and Sofia to meet with respective leaders.
The visits are part of an ongoing programme of engagement with EU leaders in the context of discussions on the future of Europe and Brexit.
But Labour leader Brendan Holwin is questioning the trip to Budapest to meet with Mr Orbán, who previously described migration as a 'poison' and suggested his country does not need a 'single migrant'.
Mr Howlin has called for an explanation as to why the visit was not announced until now, and why the Dáil was not informed on December 13th in response to a parliamentary question.
Deputy Howlin said: "A last minute visit by the Taoiseach to the Hungarian Prime Minister Viktor Orbán appears to have been added to his agenda with little publicity.
"I understand the Taoiseach will stop off in Budapest to meet Orban on Thursday en-route to Bulgaria which was a visit planned to tie in with their upcoming Presidency of the EU Council.
"In the last Taoiseach's Question session in the Dáil on December 13th, I specifically asked the Taoiseach about his planned visits over the next six months.
"The Taoiseach either misled the Dáil on that date or else these visits has been arranged at the last minute and kept secret until now."
Hungarian Prime Minister Viktor Orbán at the Office of the Prime Minister in Budapest, Hungary in 2011 | Image: UN Photo/Paulo Filgueiras
Mr Howlin claims the visit tomorrow will be seen as "an implicit endorsement by the Taoiseach and Ireland of the policies that Orbán's government has pursued".
"For Orbán this will be a prestigious visit. However, the Hungarian Prime Minister has implemented policies that many have described as anti-democratic, against EU values and the rule of law".
Speaking before his departure, Mr Varadkar said: "These visits to my European Council colleagues, PM Orbán and PM Borissov, in Budapest and Sofia, are a good opportunity to develop a deeper understanding of the challenges and opportunities facing our countries and the EU in 2018.
"I will take the opportunity to highlight Ireland's priorities for Phase 2 of the Brexit negotiations, and to thank the prime ministers for their support to date.
"I will also set out Ireland's position on key European issues including the debate on the future of Europe and the EU’s multi-annual financial framework post 2020."