The European Commission had indicated it wanted to make official its proposal to slash Europe's planet warming emissions by 90 percent within the next 15 years in the first quarter of 2025.

But it has so far failed to do so -- to the worry of green groups and lawmakers, who fear the target might fall victim to Brussels' new push to revamp the bloc's economic competitiveness.

"Clearly we need a bit more time," Wopke Hoekstra, the EU's climate commissioner told a press briefing, adding that talks continued with member states and the European Parliament.

"We're still full of ambition, and I hope, and I'm confident, that I will have secured a landing zone before summer".

The 90 percent reduction in net greenhouse gas emissions relative to 1990 is considered a stepping stone towards the EU's broader goal to reach climate neutrality by 2050.

The latter is at the heart of the European Green Deal, a landmark package of measures that defined commission chief Ursula von der Leyen's first term in office but has since come increasingly under fire.

Right and hard-right gains across Europe and the return of Donald Trump to the White House have focused Brussels' attention on defence and competitiveness -- which critics of climate action say is hindered by green rules.

Some countries, such as the Czech Republic, see the 90 percent goal as unattainable.

Italy has suggested it be lowered to 80 or 85 percent, while France warned Brussels should refrain from setting targets without detailing how to meet them.

On Thursday, Hoekstra expressed optimism that the target would not be lowered -- saying that 90 percent was his "goal" -- but did not rule out changes.

"That clearly is our starting point," he said, adding that however "we will need some pragmatism in how to get there".

"We need to make sure that the transition, the transformation we embark on, is also an asset rather than a liability in terms of competitiveness".