Green Party candidates in next year's European and local elections will have to offer guarantees that they do not hold shareholdings in controversial companies.
The decision was taken following publicity about Dún Laoghaire TD, Mr Ciaran Cuffe's ownership of shares in six oil companies. His offer to resign as the party's Dáil spokesman on the environment was accepted quickly during a meeting yesterday in Leinster House of the party's Parliamentary Party.
The Dún Laoghaire TD said he had already been in contact with his investment advisers in the United States, the Baltimore-based Brown Investments.
"I intend disposing of the shares in the companies that I am unhappy with without delay," said Mr Cuffe, who has $68,000 worth of oil shares in a portfolio worth $1.3m.
The party leader, Mr Trevor Sargent, will take over responsibility for the brief until the summer break, when it will pass to the party's deputy leader, Ms Mary White.
The controversy, said Mr Sargent, is "a stark reminder" to potential party candidates that their private lives must not be in conflict with the Greens' founding principles.
They will have to offer satisfactory declarations to the party's general secretary, Mr Stiofáin Nutty, before they will be ratified to run in the local and European Parliament elections in May 2004.
The Greens' six-strong Parliamentary Party discussed the issue yesterday morning, before Mr Sargent met later with party staff, including Mr Nutty.
Later, Mr Sargent told The Irish Times: "It has been a very serious and traumatic situation for Ciaran. He has paid the price.
"But it raises questions about the whole issue of ethical investment in Ireland.
"The issues raised by this debate are much broader. It is important that State or personal investments are evaluated on the basis of ethical issues, as well as on purely financial returns.
"All members of the Parliamentary Party fully accepted Ciaran's explanation that these difficulties arose because he had inherited these shares from his late mother."
However, the Dún Laoghaire TD, whose mother, Patricia, was the sister of Robert Kennedy's wife, Ethel, will continue to be the party's justice spokesman.
In a personal statement carried in the party's official press statement, Ms Patricia McKenna MEP said his resignation "was the correct thing to do given the lack of judgement shown".
Later, she told The Irish Times: "I do think that we were damaged by this. He didn't go out to deceive anyone, but our problem is that we are the party that occupies the high moral ground in politics. When you do that you have to live by higher standards, though it is a bit unfair that a party should be made responsible for the shares bought by the mother of a party member."
However, she said the controversy could have longer-term benefits.
"It is something that the party had never considered before. We just took it for granted that nobody would have unethical investments.
"It was very bad judgement to have those shares while some of us were outside urging people to boycott Esso".
She said she had received "hassle" from party members for staying quiet on the issue until yesterday. "I wanted to wait to see what would happen," she said.
Cork North Central TD, Mr Dan Boyle, said: "It has been a difficult day. There is a big human side to all of this. Some of the coverage of all of this has been quite prurient."