Germany says high costs might make some firms move outside the EU
EU environment ministers are meeting in Luxembourg amid pressure to revise EU plans to cut greenhouse gas emissions because of the cost to industry.
EU leaders aim to finalise an EU climate change package by December, but Italy and Poland are among a group of countries voicing doubts about it.
A UN climate summit is to take place in Poznan, Poland, in early December, adding to the pressure on EU ministers.
The EU aims to cut CO2 emissions by 20% by 2020, compared to 1990 levels.
But Italy's Environment Minister Stefania Prestigiacomo, quoted by the AFP news agency on Monday, said "the package as it stands right now is not suitable... significant changes are needed".
One of the chief concerns raised about the package is the proposal to introduce full auctioning of CO2 emission permits for power generators in 2013.
Emission quotas are allocated for free under the EU's current Emission Trading Scheme (ETS), but they are traded in a carbon market designed to give industry a financial incentive to cut emissions. Heavy polluters can buy extra permits from plants which emit less than the target figure.
With the economic downturn biting, Italy and eight countries in Eastern and Central Europe are unhappy at the burden of emission cuts they are expected to bear.
Poland and other former communist countries argue that they made big sacrifices when they closed heavily polluting factories in the 1990s.
Meanwhile, Germany is among those expressing fears about "carbon leakage" - the possibility of European industries moving to countries where there is little or no restriction on emitting CO2.
Last week EU leaders pledged to aim for an agreement on the climate package by December, but said the measures must be applied in a "cost-effective manner... having regard to each member state's specific situation".
Speaking to Italy's Corriere della Sera newspaper at the weekend, Ms Prestigiacomo said rival global powers ought to share the cost of meeting the emission targets set by the 1997 Kyoto Protocol.
"Does it make sense for us [the EU] to take on the burden of the pollution of the world, when the ones to back out of Kyoto were countries like the United States, India, and China?" she asked.
She admitted that Italy was "doing very badly over Kyoto - we have a trend showing a 13% growth in emissions, instead of a 6.5% reduction".
In a year's time the UN will stage an international conference in Copenhagen aimed at charting a post-Kyoto course to tackle the impact of climate change.
The UN Secretary General, Ban Ki-moon, has urged the EU to "continue to provide leadership on climate change, including through its ambitious energy and climate policy package".