"Bodies... the exhibition", which has toured a number of countries, consists of 13 corpses and around 250 body parts which have undergone a process known as "plastination" which preserves human tissue permanently using liquid silicone rubber.

"We are investigating this case to check whether the corpses were not desecrated and whether all procedures needed to mount such an exhibition in Poland were carried out," a spokesman for the Warsaw prosecutors' office, Mateusz Martyniuk, told Reuters.

The exhibition, which has also drawn criticism from some Polish politicians, is housed in a Warsaw shopping mall and is scheduled to run until mid-July. The organisers said they had met all legal requirements to bring it to Poland.

"The exhibition entered the European Union a few months ago and in line with all sanitary procedures, customs regulations and others," said Agnieszka Rojewska from Media Metropolis, the public relations agency promoting the display in Poland.

She said more than 10,000 people had visited the exhibition since it opened a week ago. Its chief medical adviser is Roy Glover, professor emeritus of anatomy and cell biology at the University of Michigan.

Sanitary officials expressed concern. "Thirteen dead people appear out of the blue in the centre of Warsaw. It provokes the deepest astonishment, amazement and suspicion," said Deputy General Sanitary Inspector for Poland, Jan Orgelbrand.

He invoked the spectre of the Nazi death camp of Auschwitz, located in southern Poland, where the remains of murdered Jews were used in the manufacture of various products.

"The human being is sacred... A 'beautiful' lamp made of human skin in Auschwitz is the riposte to the question of where the human being ends and where art begins," he said.

Poland was home to one of the world's largest Jewish communities before the Nazis slaughtered most of them during World War Two in camps such as Auschwitz, where some 1.5 million Jews from all over Europe were killed.

Comment among people viewing the exhibition was mixed.

"There are some critical opinions about this, but I don't agree with them. That's what we are like," visitor Anna Jurek told Reuters.

Last year, the "Bodies" exhibition also stirred controversy in the United States. The promoter agreed to stop using remains of undocumented origin in the New York display after a probe by the state attorney general.