Car makers are not doing enough to meet the European Union's proposed targets for cutting carbon dioxide emissions, with several Japanese car brands facing the biggest challenge to make the grade, a report said on Tuesday.

Overall, car makers will have to cut CO2 emissions by 17 per cent to reach the proposed goals for 2012, the report by environment group T&E said.

French and Italian car makers are furthest along that road, while Germany's luxury BMW brand is making the fastest moves to catch up, added the report, based on European Commission sales data from 18 EU countries.

The study comes a week before European lawmakers reconvene after a summer break for a battle over one of the EU's most hotly-contended pieces of environmental legislation.

'We're seeing a response to the threat of legislation,' said T&E director Jos Dings, but he added that moves to weaken and slow the legislation could quickly remove that incentive.

As part of its drive to lead the world in fighting climate change, the European Commission has proposed curbing average CO2 emissions from new cars to 130 grams per km by 2012, compared to current levels of around 158g per km.

The move is part of a broader EU effort to cut CO2 emissions by at least one fifth by 2020, compared with 1990 levels, in a bid to stave off the worst effects of climate change.

According to the T&E report, France's PSA Peugeot-Citroen and Renault and Italy's Fiat are the best-placed to meet their proposed goals for 2012 and will have to cut CO2 emissions by just 10 per cent, 13 per cent and 14 per cent respectively.

While Toyota and Honda rank fourth and fifth in the table of efficiency, with 15 and 16 per cent cuts to be made, Nissan, Mazda and Suzuki are three of the four worst-performing brands and face heavy cuts.

Suzuki has the hardest task of all, and would have to cut emissions by 25 percent by 2012 to make the grade.

Environmentalists say tough rules are needed for cars, one of the biggest sources of pollution in the 27-country zone, and they would also help European consumers by cutting their dependence on imported oil at a time of soaring gasoline prices.

But Europe's big auto manufacturers have been lobbying hard to have the plans delayed and diluted, saying they put thousands of manufacturing jobs at risk.

Germany in particular is working hard to protect its auto industry, which has traditionally focused on heavy, powerful cars like those of BMW, Mercedes and Audi, with high greenhouse gas emissions.

Yet the report also showed that BMW made the biggest efficiency gains last year, cutting CO2 emissions by 7.3 percent in 2007, compared with a European average of 1.7 percent.

'BMW has shown that even premium car makers can seriously reduce CO2,' said T&E's Dings. 'That said, BMW has not yet closed the gap.'

BMW's average CO2 emissions from new cars was 170g per km last year, compared with 184g per km in 2006.-Reuters