The Green Party TD Mr Ciaran Cuffe is taking legal advice over an evening newspaper story which claimed he had invested in a company which has website links to "pornography".
The article in the Evening Heraldsaid Mr Cuffe had bought shares in German-based condom manufacturer Condomi. The site has links to a magazine of "erotica" and to information about sex products.
In a statement issued this evening, Mr Cuffe said he felt he was being "pilloried" and that he had taken legal advice on the article.
He said he had invested in two ethical investment funds, the Stewardship Fund run by Friends First and the Green Effects Fund managed by Dolmen Securities.
"These funds have shares in companies such as Solarworld which generates and operates solar power plants; Neg Micon which designs and manufactures windturbines; and Mano which makes bicycle and snow-boarding products," he said.
"A small part of the Green Effects Fund is invested in a company called Condomi. I understand that the core business of this company is the manufacturing and distribution of condoms. Condomi works closely with AIDS relief organizations, with the UN and with the South African government in fighting the AIDS and HIV epidemics."
Mr Cuffe's statement added there was a link from the magazine on Condomi's website to another company that manufactures erotica with religious themes.
"I accept that this linked site could be offensive to people's religious beliefs. However, I don't feel that I should be responsible for companies that are linked to the website of a company that I have invested in."
The TD said he had tried to get the best professional advice to ensure that his assets were invested ethically.
"I feel I'm being pilloried, and I am taking legal advice on the story that appeared in the Evening Heraldtoday. If there are companies in the fund that do not comply with the ethical criteria used, I will raise this issue with the fund manager," Mr Cuffe said.
Mr Cuffe attached a list of the ethical criteria taken into account by his fund managers when they are investing clients' monies. The Green Effects Fund excludes investment in, amongst other things, companies which produce or market nuclear energy products, arms, genetically modified food products or which discriminate against women or use child labour.
He told RTE Radio One News today he would be seeking a full apology from Independent News & Media, which owns the Evening Herald.
Mr Cuffe resigned as environment spokesman for the Green Party earlier this year after it emerged some shares bequeathed to him by his late mother were invested in oil companies.
The TD had disclosed his holdings in the Dail Register of Members' Interests. He later sold the shares and pledged to invest the money in ethical funds and companies.