Explorers' great hopes for finding a legendary Nazi "gold train" in Poland appear to have been dashed after extensive digging found no train or tunnel at the site.

The legend has sparked a gold rush, drawing in explorers and treasure hunters from across Europe to Poland's south-western town of Walbrzych, and prompting local authorities to dream about a great inflow of tourists and money.

The local legend says in 1945, the Nazi Germans hid a train laden with gold and valuables in a secret tunnel nearby as they were fleeing the advancing Soviet army at the end of the Second World War.

Last week two explorers - Andreas Richter, a German, and Piotr Koper, a Pole - moved in with heavy equipment and dug deep at a site near rail tracks in Walbrzych, following comments by residents who said they had knowledge of the train's existence.

Mr Richter and Mr Koper said last year that their own tests using earth-penetrating radar confirmed a train was at the site.

But the explorers' spokesman, Andrzej Gaik, told The Associated Press that they found "no train, no tunnel" there and that the machines were covering over the three pits that cost 140,000 zlotys to dig.

Saying "hope dies last", Mr Gaik said a smaller-scale search using probes will resume at a nearby site in September.

The dig confirmed findings by experts from a university in Krakow last year who used magnetic equipment but found no trace of train or tunnel, Mr Gaik said.

Legend holds that an armed train loaded with treasure disappeared after entering a complex of tunnels under the Owl Mountains, a secret project known as "Riese" - or Giant - which the Nazis never finished.

The area belonged to Germany at the time, but has been part of Poland since the borders were moved in the postwar settlement.