BRUSSELS - Austria is seeking support from other European Union countries for its legal challenge to the bloc's rules labelling investments in gas and nuclear power plants as climate-friendly, the climate minister said on Wednesday.

The anti-nuclear government, which has also criticised the EU's plan to label gas, a fossil fuel, as green, has prepared a lawsuit to challenge the EU law adding the fuels to the "taxonomy" system of labelling green investments.

"We have several other states who've 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," Austrian climate minister Leonore Gewessler said.

Luxembourg has already backed the lawsuit.

The gas and nuclear rules have been subject to a year of intense debate, with EU governments deeply divided. The European Parliament last week approved the law, which Brussels says will help the EU shift to clean energy, but which campaigners say undermines Europe's leadership in tackling climate change.

"We will file a lawsuit at the European Court of Justice to prevent this greenwashing programme," Gewessler said when she arrived at a meeting of EU environment ministers.

Austria's lawsuit will argue that neither fuel deserves a green label. When burned to produce energy, gas produces planet-warming emissions that are fuelling climate change. But it emits less than coal, and some EU states see it as a temporary alternative to replace the dirtier fuel. Nuclear energy is free from CO2 emissions but produces radioactive waste.

The suit will also question whether Brussels had the power to make the rules using a "delegated act", a type of law that EU countries and lawmakers can veto, but cannot make changes to.

EU financial services chief Mairead McGuinness last week said the law would ensure that private investments in gas and nuclear met "strict criteria". The EU taxonomy does not ban investments in fuels that are not labelled as green.

Austria's lawsuit could be filed in a few months, after the law has entered into force.

(Reporting by Kate Abnett, editing by Marine Strauss and Angus MacSwan)