Environmentalists voiced anger Tuesday that Germany is seeking to soften European carbon emission limits for passenger cars to protect its powerful auto sector.

Greenpeace said "the European parliament must stay firm and reject Germany's demands, which only serve to harm the climate, drive up costs for consumers and stifle technological innovation".

Chancellor Angela Merkel has cited the need to protect jobs as she has opposed stricter EU carbon limits that aim to reduce the role of gas-guzzling cars in warming the planet's climate.

EU environment ministers meeting in Luxembourg Monday delayed a decision on whether to tighten the limit to an average of 95 grams of CO2 per kilometre by 2020.

Germany wants the limit to be phased in until 2024, and to apply to only 80 percent of cars in 2020.

EU Energy Commissioner Guenther Oettinger said he could understand Merkel defending her country's industrial interests but said that in her position "you can't afford to do that much lobbying every day, only once in a blue moon", according to German magazine Auto Motor und Sport.

Germany's luxury car makers such as Daimler and BMW tend to make larger cars on average than other European manufacturers and believe the stricter limits would put them at an unfair disadvantage.

Germany's manoeuvring sparked media criticism.

"Daimler and Co can breathe easy again," said a commentary in German daily the Neue Presse of Hanover. "Germany's biggest auto lobbyist is sitting directly at the levers of power.

"For years Angela Merkel has portrayed herself as a climate activist, and for years she has prevented stricter carbon dioxide levels for new cars."

Industry expert Ferdinand Dudenhoeffer of Duisburg-Essen university has said the delay would hurt investment in cleaner electric and hybrid designs and bore the risk "that electric mobility in Europe will die".

Daimler CEO Dieter Zetsche said he was confident a compromise would be reached before year's end that could be backed by the auto industry, governments and environmental groups.

A deal could involve a temporary exception for larger vehicles, or rewards for a greater share of electric and hybrid cars, he said, according to Auto Motor und Sport.

He also defended Mercedes-maker Daimler, saying that half of the more than 10 billion euros ($13.5 billion) it would spend on research and development in the next years would go into carbon reduction efforts.

Meanwhile, German media seized on a report that the country's wealthy Quandt family, who own a 17.4 percent stake in BMW, donated 690,000 euros to Merkel's conservative Christian Democratic Union party on October 9.

The family denied there was a link to the emission issue, the Frankfurter Allgemeine Zeitung daily reported, quoting a family spokesman as saying that the family had for decades donated to parties.

The spokesman also said the donation had been agreed months ago and was intended to reward "the very successful effort of the chancellor in resolving the eurozone crisis".