Sprawling across 150,000 hectares, the Bialowieza forest stretches across Poland's border with Belarus

Environmental groups on Tuesday lodged a complaint with the European Commission over Poland's large-scale logging plans in the Bialowieza forest, which includes Europe's last primeval woodland.

"We risk turning this into a tree plantation and reducing our natural heritage into blocks of wood," Greenpeace Poland head Robert Cyglicki told reporters, alongside representatives from six other groups including the Polish branch of the Worldwide Fund for Nature (WWF).

Poland's Environment Minister Jan Szyszko last month gave the go ahead for the large-scale logging—despite protests from scientists and ecologists—to combat a spruce bark beetle infestation.

"The Commission is concerned about the recent decision of the Polish authorities," EU environment spokeswoman Iris Petsa told AFP on Tuesday, adding that the institution had reached out to Warsaw and "will decide on any further steps" based on replies it received Monday.

Under the new plan, loggers will harvest more than 180,000 cubic metres (6.4 million cubic feet) of wood from non-protected areas of the forest over a decade, dwarfing previous plans to harvest 40,000 cubic metres over the same period.

The environmentalists take issue with the government's rationale, saying "the intensive wood extraction is a threat for priority habitats and species".

Poland's environment ministry gave the go ahead in March for large-scale logging in the Bialowieza forest to combat a spruce bark beetle infestation

"Contrary to what the minister of environment says, the bark beetle outbreak does not pose any threat to the habitats," Przemyslaw Chylarecki from Polish environmental group Greenmind said in the joint statement.

The groups said the logging plan, which could begin as early as this spring, violates EU conservation law.

"We cannot challenge this decision under Polish law, so complaining to the Commission is our last resort," said lawyer Agata Szafraniuk from the non-profit organisation ClientEarth.

"In the past, breaches of EU nature law have led to hefty fines and withdrawal of funding. We hope the minister will reconsider before this irreplaceable forest is lost forever."

Sprawling across 150,000 hectares (around 370,650 acres), the Bialowieza forest extends over the Polish border with Belarus, where it is entirely protected as a nature park.

Designated a UNESCO World Heritage site in 1979, the forest is home to 20,000 animal species, including 250 types of bird and 62 species of mammals, among them Europe's largest, the bison.

Europe's tallest trees, firs towering 50 metres high (160 feet), and oaks and ashes of 40 metres, also flourish here, in an ecosystem unspoiled for more than 10 millennia.