The Austrian environment minister said that "several other states have been very critical of, and very vocal also, in their criticism on the delegated act and so we will also look for further allies in the lawsuit."
Austria wants the European Court of Justice to rule on whether the Commission was allowed to issue a Delegated Act to label gas and nuclear as green, the country's minister said on Wednesday.
A controversial plan by the European Commission to include gas and nuclear in its taxonomy -- a planned EU classification to give the financial sector clarity on which economic activities can be considered sustainable -- was approved by MEPs last week with Austria immediately announcing it will challenge the vote in court.
Speaking from Luxembourg ahead of an informal meeting of EU environment ministers on Wednesday, Leonore Gewessler stressed that "from the very beginning, Austria was strongly opposed to greenwashing fossil gas and to greenwashing nuclear in the taxonomy."
"We will file a lawsuit at the European Court of Justice to prevent this greenwashing programme, I cannot call it otherwise, to come into force."
"There is a legal period of two months after the entry into force that is there to file the suit for the annulment of the legislation under the treaties," she explained, adding: "Of course, we will respect this time frame."
Luxembourg has also announced it will turn to the courts over the issue but Gewessler said other member states could join them.
"Several other states have been very critical of, and very vocal also, in their criticism on the delegated act and so we will also look for further allies in the lawsuit," she told reporters.
Environmental NGOs, including Greenpeace and WWF, have also condemned the vote by the European Parliament with Greenpeace also considering a legal challenge.
Opponents argue that adding branding gas and nuclear as sustainable could lead to billions of euros being invested in these two energy powers rather than in renewables or other green technologies which would, in turn, endanger commitments made under the Paris Climate Agreement as well as the European Climate Law.
These plan for the bloc to become the world's first carbon-neutral continent by 2050 and to cut its greenhouse gas emissions by at least 55% by 2030, compared to 1990 levels.
The taxonomy, the Austrian environment minister stressed on Wednesday, is "a tool where financial markets, investors, ordinary people who want to invest their money into something good and useful and green and climate-friendly need to have the certainty that wherever there is a green label on, they are truly green projects."
"So neither fossil gas, nor nuclear fulfil the criteria for really truly green investments. And we also question whether the Commission has the power to regulate this in a delegated act, and all of this will be put in the lawsuit," she concluded.