WARSAW, April 29 (Reuters) - European Union countries are split over the bloc's next climate target, as they prepare for tough negotiations to set an EU goal to cut greenhouse gas emissions by 2040.

The European Commission is preparing a proposal for the EU's 2040 climate target, aimed at keeping countries on track between the EU's existing targets to cut net emissions 55% by 2030, from 1990 levels, by 2030 and reduce them to zero by 2050.

Brussels had planned to propose a 90% net emissions cut for 2040 last month, but delayed this amid a pushback from some countries and lawmakers, who must approve the goal and are concerned about its costs for struggling European industries.

"We think it's a good target," Mika Nykänen, Finland's state secretary for climate told Reuters, of the 90% commitment, on the sidelines of a meeting of EU environment ministers in Warsaw.

"We need an attractive, solid investment environment in Europe, and if we change the big targets or change the policies, it will create uncertainty among investors and companies," Nykänen said.

Denmark, the Netherlands and Slovenia are among those backing 90%. Governments including Italy and the Czech Republic oppose, citing concerns for manufacturing sectors reeling from U.S. tariffs and cheap imports.

"We don't support it just now, the reason is the impact on the heavy industry," Czech environment minister Petr Hladík said on Tuesday.

Europe is the world's fastest-warming continent and is experiencing worsening droughts and other extreme weather linked to climate change.

But governments are grappling with other priorities including industrial competitiveness. Negotiations on past EU climate targets have stoked divisions between richer and poorer countries, with coal-reliant Poland among those concerned about the cost of the energy transition.

Estonian environment minister Andres Sutt told Reuters the Baltic nation had calculated it can cut net emissions 80% by 2040 - but that going further would depend on whether nascent carbon capture technologies scale up fast enough to cut emissions in sectors like cement making.

"Is it going to happen? As a profound believer in innovation and technology advancement, I think it will - but before one can really commit, you need to have this flexibility," he said.

Faced with political pushback, the Commission is considering flexibilities to soften the 90% emissions target.

These include counting international carbon credits towards the target, which could weaken the CO2-cutting efforts it demands from domestic industries. Germany's new government has proposed this, but said credits should be limited to covering just three percentage points of the 90% goal.

France is also interested in the idea, if there are safeguards to ensure any international carbon credits deliver real emissions reductions in other countries, a government source said.