EU member states are failing to fully disclose their fossil fuel subsidies and some are even planning to introduce new measures, according to a report published on Monday by a group of non-governmental organizations fighting climate change.

"As part of the G20 [Group of 20 industrialized and developing nations], EU governments committed to ending fossil fuel subsidies back in 2009," said the report's main author, Laurie van der Burg of Friends of the Earth.

These commitments must be turned into "concrete action plans," she added.

Carbon emissions, produced by burning fossil fuels, are considered a key factor in climate change. In 2015, the EU helped negotiate the Paris Agreement, aimed at keeping the global rise in temperatures within 2 degrees Celsius of pre-industrial levels.

The report finds that five EU countries - Britain, Germany, Greece, Poland, and Slovenia - plan to introduce new fossil fuel subsidies by 2030.

Six member states - Britain, Bulgaria, Denmark, France, Hungary and the Netherlands - claim they provide no fossil fuel subsidies, the study notes, contrary to findings by the European Commission that almost all EU states continue to provide some form of support.

In the case of Britain, the report finds that it provides more support to fossil fuels than any other member state, with tax breaks and budgetary transfers worth 12 billion euros (13,2 billion dollars) annually.

The study, compiled by experts from the Overseas Development Institute, Climate Action Network and Friends of the Earth, analyses EU member states' draft national energy and climate plans.

The final plans have to be submitted by year-end, with a view to ensure that the European Union meets its 2030 climate goals.