More that 100 councillors from the Republic and Northern Ireland are to travel to Gibraltar later this week for the annual conference of their cross-Border representative organisation, at an estimated cost of over €100,000.
Around 80 councillors from the Republic and a further 40 councillors from Northern Ireland will attend the four-day event, where they will stay at the four-star Caleta Hotel, which overlooks the Mediterranean.
At least one councillor from every county and city council in Ireland is expected to attend, with some councils sending as many as three members to the conference, which runs from Thursday to Sunday.
The cost of sending the councillors is estimated to be a minimum of €900 each.
The costs will be covered by the individual councils.
The conference is being organised by the Confederation of European Councillors, which, despite its name, only represents local authority members from Northern Ireland and the Republic.
Its name was chosen as being politically neutral to most parties on the island.
The organisation, whose headquarters is in Newtownards near Belfast, was set up in the wake of the Belfast Agreement with EU funding.
Its board is made up of councillors from the main political parties in the Republic and Northern Ireland.
Mr John Devaney, the confederation's partnership manager, said that the decision to hold the annual conference outside Ireland was taken to encourage dialogue between local politicians from differing political backgrounds.
In the past the organisation had found that "councillors can communicate better once they are outside their home grounds", Mr Devaney said.
Mr Devaney said that another reason for holding the conference in Gibraltar was that the organisation would be studying cross-border relations between Britain, Spain and the residents of the Rock of Gibraltar.
According to the confederation, the costs of attending the conference include a €250 conference fee, flights costing in the region of €350, and hotel rooms at £75 sterling each per night.
The conference includes a day trip across the straits of Gibraltar to Morocco, during which councillors will learn about migration issues on borders between rich and poor nations.
A half day has been devoted to a study tour of the Rock of Gibraltar