An Taisce, the heritage group, is taking legal action against the British government, claiming that it has failed to consult the Irish people on its next generation of nuclear power stations.
The group says the new developments could have a big impact on Irish citizens' lives if there are leaks or accidents.
The British government has given approval for the £14bn (€16.5bn) Hinkley Point C plant in Somerset, to be built by the French energy company EDF, which operates eight of Britain's existing nuclear power stations.
The new plant will produce 7 per cent of Britain's energy needs. An Taisce will go to the High Court in London in December to seek a judicial review challenging the legality of the decision by Ed Davey, the British energy minister, to grant permission to build the plant, which will be 150 miles from the Irish coast.
An Taisce denied that the move was a PR stunt that had little chance of success pointing out that, as a charity, it had a duty to think hard before taking legal action.
But its decision to go to court is likely to raise questions politically as to the appropriateness of the action.
The group is questioning whether the development complies with both the EU's Environmental Impact Assessment directive and the UK's own regulations on trans-boundary impacts and consultation.
In a statement to the Sunday Independent last night, James Nix, spokesperson for An Taisce, said: "This case is not about interfering with the right of the UK authorities to make their own decisions, nor about being pro- or anti-nuclear.
It is about ensuring that the rights and interests of the Irish public and their concern for their environment are not excluded from those decisions, and that the Irish public is properly consulted in accordance with the law on a project of this nature."
The charity claims the British government failed to properly consult the Irish public before granting consent for the plant.
"Despite the nuclear power plant being nearer to the coast of Ireland than it is to Leeds, the UK decided not to consult with the Irish public about the decision before it granted consent in March," An Taisce said in a statement.
"The first time many Irish people learnt about the nuclear power plant proposal was when the decision was announced."
Greenpeace has launched a separate legal challenge on the grounds that the British government has not said where it would deposit the plant's nuclear waste.
The UN is also taking a close interest in the plant's development in response to concerns raised by green parties in several European countries which complain that the UK has failed to consult adequately. A UN committee will examine whether the plant poses environmental threats that fail to respect national borders.
In addition, the European Commission must decide whether the UK is allowed to offer nuclear power consortiums an agreed "strike price" for their electricity, which critics say equates to a subsidy and is anti-competitive.
Hinkley Point is seen as a test case that will set a precedent for other EU states, such as Poland and the Czech Republic, which are keen to expand their nuclear power programmes.
Irish governments have in the past asked London to close the nuclear reprocessing plant at Sellafield in Cumbria over concerns about pollution of the Irish Sea and fears that an accident could harm Ireland's environment severely.
A request by Dublin at a UN tribunal for the plant's closure was rejected.