Polish prosecutors want to question two people in Sweden who they believe orchestrated the theft last month of the infamous "Arbeit macht frei" sign at the entrance of the former Nazi death camp of Auschwitz.

Polish police arrested five local men in December just days after the theft of the sign, which in English means "Work sets you free". They also recovered the sign, which had been cut into three pieces to fit into the thieves' getaway car.

"We have asked Sweden to confirm the personal data of two people we suspect of participating in this crime and we want to question a third person from Sweden as well, but this person has no direct link with the case," prosecutor Artur Wrona said.

Prosecutors have already said the five detainees are petty criminals who acted on orders from somebody outside Poland.

"One (of the two sought) is the mastermind behind this theft and the other is the one who brought the car to Poland which later served during the robbery," Wrona told a televised news conference in the southern Polish city of Krakow on Wednesday.

"Our next steps depend on Sweden's response, but we believe we have enough evidence to be able to press a charge of incitement to theft against at least one of these people and perhaps against both," Wrona added.

Poland may issue a European arrest warrant for the two people concerned, Wrona said, but he denied media speculation that they might be linked to neo-Nazi organisations.

Sign replica may remain

Prosecutors say the theft of the sign was money-driven but it had stirred fears of a possible political motive as the sign is a powerful symbol of the Holocaust committed by Nazi Germany against the Jews during World War Two.

Up to 1.5 million people, mostly Jews, perished at Auschwitz during the German occupation of Poland. A total of 6 million Jews died in the Holocaust at the hands of the Nazis.

The Auschwitz site is now a museum encompassing 155 buildings -including the notorious gas chambers - 300 ruined facilities and hundreds of thousands of personal items. It is on the UNESCO world heritage list.

The sign, which was forged by a Polish prisoner held at Auschwitz, is undergoing laboratory tests and will be returned to the museum before Jan. 20, Wrona said. At present a replica of the sign is installed over the former camp's entrance.

Poland's Culture Minister Bogdan Zdrojewski said on Wednesday it was unlikely that the original sign would be reinstated there.

"We think it's too risky to have the original sign outside where it is prone to different weather conditions. It could be exhibited in the parts of the museum, which are inside the building and more safe," Zdrojewski was quoted as telling the broadcaster Polsat News.

The museum will hold celebrations on Jan. 27 to mark the 65th anniversary of the camp's liberation by Soviet troops.