Polish President Andrzej Duda on Monday defended his country's ongoing reliance on coal as a main source of electricity during the opening of a UN climate conference in Poland.

"Using your own natural resources - in Poland's case, coal - in order to be able to ensure energy security is not in opposition to climate protection and progress in climate protection," the president said.

Duda said Poland was following a path of "balanced development" in its climate protection action and that the country had continuously been reducing its greenhouse gas emissions over the past 30 years as long as the economy continued to grow.

For two weeks, representatives from just under 200 states are in Poland to focus on fleshing out the rules for financing and implementation of the 2015 Paris climate agreement.

The pact provides an outline for countries working together to limit the Earth's warming to between 1.5 and 2 degrees Celsius.

Most efforts to prevent the planet heating up relate to stopping the release of greenhouse gases as soon as possible.

Duda said at the opening of the climate conference that Poland, as host, was prepared to contribute to the fight against climate change.

However, 80 per cent of Poland's electricity is still powered by coal, and the current Polish government has not given any indication that it plans to change this.

Greenpeace activists criticized the choice of Poland as conference host, arguing that the country could not serve as a good role model.

The environmental group demanded that Poland implement the "Just Transition" declaration signed on the first day of the conference as soon as possible. The declaration pushes for a fair transition from fossil fuels to a sustainable and low-emissions economy.

Though Warsaw says it supports the move away from coal, it still backs the coal industry at the same time, say the environmentalists.