WARSAW (REUTERS) - Poland said on Monday (July 31) it would press on with logging the country's primeval Bialowieza forest in defiance of a ruling by the European Union's top court, saying it needed to cut down trees to defeat insect pests.

The European Court of Justice (ECJ) ordered Poland last week to immediately stop large-scale logging in the ancient forest, one of many cases that has pitted the nationalist, eurosceptic government in Warsaw against the bloc.

But Poland said it would keep logging in the forest, a UNESCO World Heritage site which straddles the border between Poland and Belarus.

"We are acting in line with the EU laws," Environment Minister Jan Szyszko told a news conference on Monday.

He argues that "protective measures" in Bialowieza are needed to stop the biggest beetle outbreak in decades.

"We have to fulfil the protective measures plan and this is what we are doing," Konrad Tomaszewski, a representative of the state forest management agency, told the same news conference.

The logging has triggered protests by environmentalists and raised concern in the European Commission, which has also started legal action against Poland over its judiciary reforms.

The EU's executive Commission earlier this year sued Poland at the European Court of Justice over the logging.

Environmentalists say the beetle is only a pretext for Szyszko.

They argue that he favours logging because it brings more revenues to the local community and helps to boost support for the ruling Law and Justice party.

Szyszko approved tripling of the quota of wood that can be harvested in one of three administrative areas of the Bialowieza Forest in March 2016.

Following Poland's reaction to the court ruling, the European Commission said Warsaw must comply with the no-logging decision.

Szyszko said he is not worried about possible EU fines for non-compliance with the ruling.

He estimated that a halt to the protective measures could cost 2 billion zlotys (US$552.03 million) in damage to nature, without elaborating.

Szyszko brought a jar of Bialowieza beetles to the news conference, saying they were enough to kill a thousand trees.

But non-government organisations including Greenpeace and Wild Poland Foundation say the vast majority of trees felled so far were unaffected by the beetles.

They also say 2017 timber targets set for all three administrative areas of Bialowieza have already been significantly exceeded.

NGOs also say that while the logging continues, the foresters and guards from the agency that oversees state-run forests have become more aggressive towards protesters.