The opening of a €600m super-museum in Berlin has been postponed to next year, raising sceptical eyebrows among locals wary of the German capital’s growing tendency to deliver large public building projects late and over budget.

The Humboldt Forum will host blockbuster exhibitions about world culture, anthropology and ethnology, and is also expected to delicately touch on Germany’s under-explored colonial history.

Described by some as Berlin’s answer to the British Museum, it is housed inside the Stadtschloss, a reconstructed Prussian palace that was torn down by the Soviet administration of East Berlin in the 1950s. It was originally scheduled to open on 19 September with an exhibition to mark the 250th birthday of its namesake, the explorer and polymath Alexander von Humboldt.

But on Wednesday the foundation charged with planning the museum conceded that because of technical issues, “it is not realistic to expect to have the building ready to use as planned by the end of 2019”.

Site of the new museum as seen from the roof of Berlin Cathedral in March. Photograph: Alexander Becher/EPA

A wrongly programmed subterranean climate control system and pipework blocking emergency exit routes were among the factors that Petra Wesseler, the president of the Federal Office for Building and Regional Planning, blamed for the delay.

Small engineering flaws have already snowballed into bigger problems for the Humboldt Forum: leading international museums including the Louvre, London’s Victoria and Albert Museum and New York’s MoMA reportedly declined to loan it about 150 exhibits while it was still a construction site.

A launch exhibition centred around ivory was also postponed to 2020 because the material is particularly sensitive to sudden changes in temperature and humidity.

Among Berliners, the museum’s sputtering non-start has awoken tragicomic memories of the German capital’s Berlin-Brandenburg airport, which still awaits completion seven years after it was shut down because of “technical difficulties” a month before its scheduled opening in 2012.

Unlike the airport, which is likely to end up costing more than three times original estimates, the rebuilding of the 15th-century city palace that houses the new museum is expected to be completed within budget. A project contentious with many Berliners since it was first mooted in the early 90s, the rebuilding of the 44,000 sq metre palace prompted protests from those who accused it of being yet another expensive pastiche reconstruction of a historic building.

The Humboldt Forum has been described as Berlin’s answer to the British Museum. Photograph: Hayoung Jeon/EPA

Some curators have also complained that the Humboldt Forum’s spectacular neoclassical outer shell is a burden to its contents, harking back to Berlin’s pre-democratic past rather than looking to the future.

In July, the French art historian Bénédicte Savoy resigned from the Humboldt Forum’s advisory board, expressing her frustration with the lack of research into the provenance of objects scheduled to be exhibited in the space.

Savoy said uncomfortable questions about the ethics of showcasing artefacts that European explorers had often taken from other continents without consent had merely been covered up by the Humboldt label “to make sure that none of its radiation leaks outside”. The Humboldt forum, she said, “is like Chernobyl”.

The former British Museum director Neil MacGregor, who chairs the Humboldt’s advisory committee, has defended the concept behind the new museum. The two Humboldt brothers, Willhelm the philosopher and his naturalist younger brother, Alexander, “sought to regard all cultures as of equal value”, MacGregor has argued. “That is a pre-colonial view of the world which we would like to use fruitfully for the post-colonial era.”

MacGregor, whose Memories of a Nation exhibition about Germany enjoyed success in Britain and the country it takes as its subject, appears to be losing a more practical argument about the new exhibition space: he has called for admission to the Humboldt Forum to be free, as it is with the British Museum.

But last month Berlin’s culture senator, Klaus Lederer of the leftwing party Die Linke, ruled that permanent exhibitions inside the space would not be exempt from the entrance fees that Berlin museums charge

Making the Humboldt Forum free for all, Lederer said, would have negatively affected smaller cultural events, such as youth and fringe theatres.