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.
"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.
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.
Persons:
Leonore Gewessler, Gewessler, Chancellor Karl Nehammer's, Karoline Edtstadler
Organizations:
Climate, Energy, Mobility, Innovation, European Union, European, Union, Greens, People's Party, EU
Locations:
European, Brussels, Luxembourg, Austria, Belgium, Austrian