The bill - which aims to create new demand for crops such as rapeseed to help Poland's struggling farmers - would set from 2003 an obligatory minimum 4.5 percent level of biofuels' shares in total domestic fuel sales.

The EU wants a two-percent minimum level of biofuels as a proportion of all fuels by 2005, gradually reaching 5.75 percent of all fuels sold by 2010.

Poland is by far central Europe's largest fuel market with annual consumption of around 10 million tonnes, of which nearly a fifth comes from imports.

Biofuels are environment-friendly and often enjoy favourable tax treatment. They have many advocates among industry players as laws limiting pollutants grow stricter around the globe. They are also seen as key in lessening dependence on imported energy.

But Orlen, Poland's top fuels group with 1.5 percent of sales already comprised of biofuels, said the bill was unfairly setting high obligatory minimum biofuel levels and violating EU law by forcing fuel sellers to use only Polish bio-components.

"While in general we are decisively in favour of getting more bio-fuels in the market, this bill is simply uncivilised," Janusz Wisniewski, Orlen's deputy chief in charge of production, told Reuters.

"We are just about to introduce a bill which violates European Union regulations and which will have to be reversed the first day after accession," he added.

"MOONSHINE" FUEL

While Orlen theoretically could win out on the bio-component import ban, Wisniewski said lack of clear-cut quality guidelines could easily lead to "moonshine" fuels flooding the market.

"In Poland there are no standards for checking the quality of bio-components in fuel and this bill may simply bring more harm than anything else," he said.

Car makers, including the Polish unit of Ford Motor, have warned in the past few days that many engines used in cars driving on local roads could not handle high biofuel levels.

The bill - which has already sparked a public debate between environmentalists, farm lobbying groups and the fuel and refining industry - also allows for a controversial government prerogative to set a minimum price for crops used in biofuels.

Biofuels are combustible fuels that can be used pure or blended with conventional fuels and are obtained by processing plant oils, sugarbeet, cereals, and organic waste materials.

They include biodiesel which is made from plant oils such as rapeseed, sunflower and soybean and bio-ethanol which uses fermented sugar beets and cereals.