There were no government officials from Britain, but the most senior British guest, Bonnie Greer, the deputy head of the board of trustees of the British Museum, said she believed more strongly than ever that the marbles should remain in London.
She argued that in London they are displayed in an international cultural context.
She said a loan was possible, but that would require Greece to acknowledge British ownership, something Greece refuses.
The British Museum holds 75m of the original 160m of the frieze that ran round the inner core of the building.
'Act of barbarism'
Their reconstruction in the Acropolis Museum is based on several elements that remain in Athens, as well as copies of the marbles in London.
The modern glass and concrete building, at the foot of the Acropolis, holds about 350 artefacts and sculptures from the golden age of Athens that were previously held in a small museum on top of the Acropolis.
The structure is Greece's answer to the British argument that there is nowhere in their country to house the Elgin marbles
The £110m ($182m; 130m euros) structure, set out over three levels, also offers panoramic views of the stone citadel where they came from.
The third floor features the reconstruction of the Parthenon Marbles.
The copies are differentiated by their white colour - because they are plaster casts, contrasting with the weathered marble of the originals.
Museum director Prof Dimitris Pandermalis said the opening of the museum provides an opportunity to correct "an act of barbarism" in the sculptures' removal.
"Tragic fate has forced them apart but their creators meant them to be together," he said.
Bernard Tschumi, the building's US-based architect, said: "It is a beautiful space that shows the frieze itself as a narrative - even with the plaster copies of what is in the British Museum - in the context of the Parthenon itself."
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