The independent senator can currently be heard promoting the sale of cauliflowers in Tesco supermarkets and endorsing HB icecream with the words "scientifically proven" on national radio.

Speaking to the Sunday Tribune this weekend, he said, "I can live easily with a few cauliflowers on my conscience. I was asked by some advertising agencies to participate in the adverts and I thought it was quite funny."

Even though Norris participated in a debate about the removal of the controversial Groceries Order in the Seanad last December, he is adamant that he has no conflict of interest in carrying out the radio adverts.

During the course of that debate, he referred to the "predatory nature of these groups" in a discussion about multinational retailers.

"I don't think there is a conflict of interest as I was very much on the side of the small corner shop in that debate, " he said.

"I have consistently spoke about the local shops in my area and I would be happy to promote them free of charge. I don't think we should be xenophobic about English supermarkets coming into Ireland but if people listened to what I said about the Groceries Order in the Seanad, they would realise I am on the local shops' side."

Norris's distinctive voice has been mimicked in a number of adverts and on the popular 'Navan Man' slot on Today FM's Last Word programme in recent years.

"I do a certain amount of radio broadcasting and I understand that there are people out there who take off my voice so why should they make money out of it when I can do it myself, " he said.

"I think that people taking off my voice is a bit silly but to be honest I am rather flattered. I used to find the 'Navan Man' sketches quite funny. I am not a bit bothered about that."

While Norris accepted the offers to do adverts for Tesco and HB, he pointed out that he has refused "very large sums of money" in the past to do adverts for the drinks industry.

Junior minister and PD TD Tom Parlon recently found himself at the centre of a controversy over public representatives participating in advertisements when he endorsed a brand of calf nuts in The Irish Farmers' Journal.

Commenting on that controversy, Norris said, "Tom Parlon may have made a technical error in that case but I would be much more concerned about the government's mistakes in areas like health and foreign policy than that ad."