Senior Green Party member Dan Boyle, who last year introduced an unsuccessful private member's bill in the Dail asking it to establish ethical guidelines for the NPRF, told the Sunday Tribune he would like to see the Government adopt the Norwegian national pension model, which has dropped numerous defence equities from its 225bn portfolio as well as companies, such as WalMart, which were judged to have ethical shortcomings.

"If it exists there why can't it exist here?" he said. "We can't have amoral investing."

The NPRF did incorporate the UN directive of principled investing in December 2006. While this gives the fund managers licence to take a more activist shareholder role regarding environmental, social and governance issues, they are still legally bound to pursue maximum returns and do not invest in any so-called ethical funds.

"The trend will be towards greater return [in ethical funds] as consumers continue to turn toward ethical choices themselves, " said Boyle. "Private investment is increasing anyway and we have these unnecessary obstacles in our own funds."

Boyle conceded that ethical investment didn't make the cut in the Programme for Government, but he expressed optimism that, with Greens at the Cabinet table, the issue had life in it yet.

"Opposition to it is not so strong to prevent it coming up, " he said. "In a five-year term, there is time to broach new ideas."

The moves drew sharp criticism from the US government, which felt American companies were disproportionately and unfairly maligned by the divestments.