WARSAW (AFP) - Poland's deputy culture minister said on Friday he saw a ground-penetrating radar image of the alleged Nazi train that has set off a gold rush, adding that he is 99 per cent sure it exists.

Local media have for days been abuzz with old lore of trains full of gold and jewels stolen by the Nazis after two men - a German and a Pole - claimed to have found an armoured train car in the southwestern city of Walbrzych.

"I'm more than 99 per cent sure such a train exists, but the nature of its contents is unverifiable at the moment," Deputy Culture Minister Piotr Zuchowski told reporters.

"I saw a good quality ground-penetrating radar image showing what the train looks like," he said, adding that he could make out platforms and cannons on the photo.

Zuchowski, who is also the national heritage conservation officer, refused to reveal the train's exact location, adding: "My understanding is that no one has accessed it since the (Second World) War."

Someone, who decades ago took part in hiding the train that is over 100m in length, passed along the information by word of mouth, Zuchowski said but did not specify to whom.

"And this person shared the information on their deathbed along with a sketch of where it could be found," he said without revealing the person's identity.

Zuchowski confirmed that the German and Pole, who wish to remain anonymous, have the right to claim a finder's fee of 10 per cent of the value of the train's contents.

"The fact that this train is armoured suggests there could be valuable objects inside" including artwork, archival documents or treasures, he said.

But he warned that the train could also be booby-trapped.

Rumours of two special Nazi trains that disappeared in the spring of 1945 have been circulating for years, capturing the imagination of countless treasure hunters.

The lore has its basis in the existence of secret underground passages near Walbrzych - including around the massive Ksiaz Castle - that Nazi Germany ordered built and where legend has it the Third Reich stashed valuables.

On Friday, dozens of curious onlookers could be seen loitering around a train track slope in Walbrzych where the train may be hidden.