European Union countries approved a flagship policy to restore damaged nature on Monday, after months of delay, making it the first green law to pass since European Parliament elections this month.

The nature restoration law is among the EU's biggest environmental policies, requiring member states to introduce measures restoring nature on a fifth of their land and sea by 2030.

EU countries' environment ministers backed the policy at a meeting in Luxembourg, meaning it can now pass into law.

The vote was held after Austria's environment minister, Leonore Gewessler of the Greens, defied her conservative coalition partners by pledging to back the policy — giving it just enough support to pass.

"I know I will face opposition in Austria on this, but I am convinced that this is the time to adopt this law," Gewessler told reporters.

The policy aims to reverse the decline of Europe's natural habitats — 81% of which are classed as being in poor health — and includes specific targets, for example to restore peat lands so they can absorb CO2 emissions.

The move by Austria's minister angered Chancellor Karl Nehammer's conservative People's Party, which opposes the law. The OVP minister for EU affairs, Karoline Edtstadler, said Gewessler's vote in favor would be unconstitutional.

Belgium, which holds the EU's rotating presidency and chairs meetings of ministers, said the Austrian government dispute would not affect the legality of the EU ministers' vote.

EU countries and the European Parliament negotiated a deal on the law last year but it has come under fire from some governments in recent months amid protests by farmers angry at costly EU regulations.

Finland, Hungary, Italy, the Netherlands, Poland and Sweden voted against the law on Monday. Belgium abstained.

EU countries had planned to approve the policy in March but called off the vote after Hungary unexpectedly withdrew its support, wiping out the slim majority in favor.

Countries including the Netherlands had raised concerns the policy would slow the expansion of wind farms and other economic activities, while Poland on Monday said the policy lacked a plan for how nature protection would be funded.