The men, identifying themselves Andreas Richter and Piotr Koper, appeared on the country's TVP public television.
In a statement they said they had "irrefutable evidence" the train existed, but failed to provide proof.
Officials have cast doubt on the claims in recent days. The military was said to be inspecting the alleged site on Friday.
Last week deputy Culture Minister Piotr Zuchowski said he was "99% convinced" that a World War Two German military train was buried near the south-western city of Walbrzych.
Local legend says a Nazi train filled with gold, gems and guns went missing near the city in 1945.
Speaking to TVP on Friday (in Polish), German national Mr Richter and Mr Koper, from Poland, said they had "legally informed state authorities about the find and have precisely indicated the location in the presence of Walbrzych authorities and the police".
Their knowledge was based on information from witnesses and on their own research, carried out with their own equipment, Mr Koper said in his statement.
He insisted they were not responsible for the "media uproar" around the case, saying confidential information provided to the authorities had been leaked.
The pair want a 10% finders' fee and have reportedly vowed to spend part of the sum setting up a museum at the undisclosed site.
Meanwhile, TVP said on Friday that the train was not in a tunnel, as previously thought, but instead buried in the ground.
The train was rumoured to have been carrying gold from what is now the Polish city of Wroclaw as the Soviet army closed in at the end of World War Two.
Local folklore said it went missing near Ksiaz castle, 3km (two miles) from Walbrzych.
In a statement earlier last week, Mr Zuchowski warned the public to stop searching for the train until official procedures to secure the find were completed.
He said there could be "hazardous substances" and there was a "huge probability that the train is booby-trapped".
Two men who claim to have found a Nazi train said to be laden with gold have gone public in Poland.