Visitor numbers crashed to just over half a million in 2020 from 2.32 million a year before.
The museum remained closed to visitors for several months last year, for the first time in its history, owing to the coronavirus restrictions.
"The period of the pandemic has been very hard for the Auschwitz Memorial, which in 2020 was closed to visitors for 161 days," the report said. "The planned budget collapsed. Almost all subject-related activity of the Museum was limited and investment projects were reduced to the necessary minimum."
Pawel Sawicki of the museum's press service said that "the number of visitors at the Memorial fell dramatically and because of this the museum was deprived of its main source of funding."
"This caused a nearly complete suspension of the educational activities in the historical section and a serious collapse of the museum's budget, wiping out a number of priority investments and projects," Sawicki added.
In the annual report, the Museum said: "Thanks to exceptional aid provided by the Polish Ministry of Culture and National Heritage and increasing (its) subsidies from PLN 25 to 31 million, the continuation of the museum’s basic activity was maintained together with workplaces."
The last large-scale event at the museum before the coronavirus epidemic spread across the country was the 75th anniversary of the death camp's liberation, held on January 27, 2020, Sawicki said.
Over 200 Auschwitz and Holocaust survivors and representatives of more than 50 countries took part in the ceremonies.
During the epidemic, the number of online visitors, however, has surged. "Interest in a virtual visit, using the panorama.auschwitz.org website, increased by over 50 per cent in comparison with the previous year," the report states.
"It is difficult to predict further developments in this respect," the museum also said in the report as it acknowledged the support from its donors. "We extend our sincere gratitude to every person, institution and organisation that has supported us financially in this difficult situation."
Opened in 1940 during the German occupation of Poland, the Auschwitz camp became the epicentre of the Holocaust. At least 1.1 million people, mainly Jews, but also Poles, Roma people and Soviet prisoners of war perished in the camp until its liberation by the Red Army in January 1945. (PAP)