Independent Senator David Norris has called UK Brexit campaigner Boris Johnson a "liar'' in a debate on the eve of the referendum.

“We all know Boris Johnson threw his hat in the ring and changed his position because he had his eye on the leadership of the Tory party,’’ he added. “And he is a liar.’’

Mr Norris said in the Seanad on Wednesday the use of the immigration issue in the UK campaign was “utterly obscene, disgusting and repulsive and it does not do credit to a great country like Britain’’.

He said everything but the issues were being discussed in the campaign.

He said it was "a particularly stupid'' idea of British prime minister David Cameron to hold a referendum.

Mr Norris said he was a reluctant supporter of Britain staying in the EU.

"I have always believed in Europe, but the Europe I believed in was a Europe of people,'' he added. "It was a social Europe; it was not a Europe of financial institutions.''

He said what had been seen recently was the naked exercise of power by unelected, unaccountable European financial institutions to the great detriment of the people.

“There is not a country in Europe where there is not revulsion against the EU and its dictatorial attitudes,’’ he added.

Minister for Foreign Affairs Charlie Flanagan said Ireland wanted the UK, "as a friend, closest neighbour and partner'', to remain a member of a reformed EU.

“This is a view which enjoys near-unanimous support within both Houses of the Oireachtas, though I recognise and respect that there is a different point of view,’’ he added.