Natural Resources Minister Jim Carr says this is not the time to phase out fossil fuel subsidies.

That's despite a green federal budget filled with environmental measures, ranging from green infrastructure and transit funding to clean technology research and development.

However, a campaign promise to "phase out subsidies to the fossil fuel industry over the medium-term" did not make the cut in the first Liberal budget.

Carr emerged from yesterday's caucus meeting to say now is "not the moment" to start ramping back government subsidies for an oil and gas sector hammered by a global glut and price decline.

Prime Minister Justin Trudeau has made combatting climate change a key platform and expectations continue to run extremely high in the environmental community.

Green party Leader Elizabeth May called the first Liberal budget a bitter disappointment.

She said the budget locks in controversial Conservative changes the Liberals bitterly opposed when they were introduced as part of a sweeping omnibus bill in 2012.

And a Conservative tax break for liquefied natural gas producers that runs through 2024 remains in place.