European Union governments have approved a one trillion euro ($A1.6 trillion) green roadmap for the bloc's lending arm that will see it stop financing fossil fuel projects and airport expansions.
Climate groups, however, say the measure does not go far enough.
The European Investment Bank's "Climate Bank" plan had been in discussion since last year when it was laid out as a sign of the EU's intent to lead on the fight against climate change.
The one trillion euros is to be spent by 2030 on climate, biodiversity and sustainability-focused projects.
The bank says "all financing activities" will also be aligned with the Paris climate agreement by the end of this year.
"It is a major contribution to Europe's role leading the way toward decarbonisation and a green, resilient and socially inclusive economy," EIB President Werner Hoyer said on Wednesday.
Environmental groups had welcomed the EIB's proposals last year but said the final version had been stripped of some of its original ambition.
Its deadline to stop funding oil and gas projects had slipped back a year, some other damaging projects would still receive backing until 2022 and road building would also continue.
"We are disappointed by the decisions of the European governments who adopted this Climate Roadmap," said Xavier Sol, director at Counter Balance, a coalition of development and environmental non-governmental organisations.
"In practice, it means the EIB will not become Paris-Aligned by the end of 2020. In light of the climate urgency, this is a missed opportunity."
Even so, the groups welcomed the formal recognition of climate change as a priority for the EIB and called the move to stop financing airport expansions a "noticeable step forward".
The EIB is expected to make another small but significant change by formally aligning with the Paris agreement commitment to limit global warming to 1.5 degrees above pre-industrial levels.
"COVID-19 is not the only crisis on our hands," Hoyer said.