Greenpeace activists on Monday hoisted banners protesting against coal use atop Poland's economy ministry in Warsaw, as a global coal conference got underway and UN climate talks entered their final week.

Around 40 activists unfurled a large blue and white banner asking: "Who rules the world? Fossil industry or the people?" Others held one printed in red-and-white saying: "Who rules Poland? Coal industry or the people?"

Police used a giant fire engine crane to remove the protesters, several of whom used climbing gear to dangle from the facade of the economy ministry.

Other anti-coal protestors outside the venue touted a massive set of pumped up plastic lungs.

One of Poland's most notorious coal problems is smog, especially in the southern tourist city of Krakow, which plans to outlaw coal-burning household stoves this month.

The two-day coal conference is being organised by an industry group, the World Coal Association, at the economy ministry. It is just miles from the Warsaw stadium hosting a second week of UN talks on curbing Earth-warming fossil fuels.

Environmentalists dressed in colourful traditional Polish costumes also unfurled a huge banner outside the stadium saying: "Stop dirty energy, empower the people".

Poland's dependence on the cheap and plentiful black stuff means it ranks fifth for carbon dioxide (CO2) pollution in the European Union, behind Germany, Britain, Italy and France, whose economies are far larger.

Coal accounts for around 90 percent of the electricity used by Poland's 38 million people -- and, say experts, there is enough of it to last another century and a half.