Two people have been confirmed dead and six are still missing after a massive cave-in at a copper mine in south-western Poland following an earthquake.

The tremor happened shortly after 9pm local time, some 1,100m underground in the Rudna mine in Polkowice.

Jolanta Piatek, spokeswoman for the KGHM Polska Miedz, or Polish Copper, mining corporation, said rescuers found one body underground. Earlier, one of nine miners brought to the surface shortly after the collapse had also died.

Five others have been taken to hospital, while nine rescue teams continue the search for those still missing.

The rescuers are receiving signals from the locators of the missing miners, but have had no direct contact with them, Ms Piatek told the Associated Press.

The German Research Centre for Geosciences in Potsdam, near Berlin, reported a magnitude-4.5 shallow earthquake in the Polkowice region at the time of the cave-in.

Work continues as usual in other areas of the mine, Ms Piatek added.

Known as the Polish State Mining and Metallurgical Combine under communism, KGHM went through restructuring and partial privatisation in 1991 as Poland shifted to a market economy.

It has grown to be one of the world's major copper and silver producers, and also has mines in Chile, Canada and the United States.