Israel has been accused of launching a smear campaign against Irish presidential candidate, Senator David Norris, after a blogger wrote about his relationship with an Israeli peace activist.

John Connolly, a 22-year-old Zionist blogger from Ealing, revealed last month that Senator Norris's former partner, activist Ezra Nawi, had been convicted of a series of crimes, including sleeping with an underage boy.

Last week, Mr Connolly wrote that Mr Norris had expressed solidarity with Mr Nawi in the Irish Parliament. It was later disclosed by an Irish newspaper that Mr Norris had written a letter to an Israeli court pleading for clemency for Mr Nawi.

Following the revelations, a number of journalists and bloggers, including columnist Ian O'Doherty of the Irish Independent and blogger Aindreas Mac, insinuated that the Israeli embassy of Ireland had leaked the letter to the press.

The embassy has strongly denied the claim, saying it has "absolutely no foundation".

Mr Connolly, who has faced accusations that he is a Mossad agent, said: "I wanted to get this information out because this man is running for president and I thought he had abused his position. If I had come across this news about any candidate, I would have published it. I disagree with him about a lot of things, not just Israel."