Poland has appealed to second world war buffs and rail enthusiasts to stop searching for a Nazi train believed to have lain undiscovered for 70 years and rumoured to carry treasure.

Authorities say they believe they have located the train in the county of Wałbrzych, after they were tipped off by a German and a Pole who said last week that they had found it and expected a finder’s fee of 10%.

The culture ministry said “foragers” had since become active in the area and urged them to stop, saying they risked harming themselves.

“I’m certain the train exists, but it might contain dangerous material,” said Piotr Żuchowski, the head of national heritage at the ministry. “This is an appeal for any further investigations to be put on hold until we have finished the necessary official procedures relating to securing the site.”

Local news reports say the train, believed to be military, went missing in 1945, packed with loot from the then eastern German city of Breslau – now called Wrocław and part of Poland – as Soviet Red Army forces closed in.

Reports said the train contained up to 300 tonnes of gold, as well as a batch of diamonds, other gems and industrial equipment. According to local folklore, it entered a tunnel in the mountainous Lower Silesian region and never emerged. The tunnel was later closed and its location long forgotten.