In a move that is rare in the art world, the gallery has filed documents in a US court claiming an 11th-century Indian statue it bought for $5 million in 2008 was stolen.

The gallery bought the bronze statue, Shiva as Lord of the Dance (Nataraja), from New York-based art dealer Subhash Kapoor.

An office manager at the dealership pleaded guilty last year to trafficking in stolen art, and the Shiva statue is listed in court documents as being illegally exported from India.

At the hearing of the charges against Aaron M. Freedman, the court heard the statue had been stolen from an Indian temple and illegally exported to the US as part of a larger smuggling project.

Dealer Kapoor is also facing charges in India over allegations of art smuggling.

The national gallery is seeking the return of the $5 million it paid for the statue, plus costs.

Documents filed in the New York County Supreme Court state the Shiva statue was one of 21 works purchased by the gallery from Kapoor over a period from 2002 to 2011, and that "further work will need to be undertaken to ensure clear title and accurate provenance of those works".

The gallery said the dealership fraudulently induced the gallery to buy the statue with false assurances of its provenance and history.

Among the documents filed was a letter of provenance with the false assertion that the statue had been acquired by an Indian diplomat before 1971, and had been out of India since then.

A lecturer in Asian art history and curatorial studies at the Australian National University, Charlotte Galloway, said proving provenance of Asian art was particularly difficult for collecting institutions.

"If you look at the history of collecting Asian art, when much of the materials came into Western collections from the colonial period, there were no laws or legislations in place which stopped a lot of this material leaving the countries concerned," she said.

"Even when the countries introduced legislation, which varies … there were no reciprocal agreements with Western countries for quite some time."

"For a long period of time, even if countries had expressed some concern, or something had been taken, it was a pretty a toothless tiger-type response."

Dr Galloway said many pieces in Asian art collections were not only ancient, but anonymous in terms of creators, making their provenance difficult to track.

"From that point of view, too, if you go to something like the art-loss register, you're really relying on images from photographic representations of things, because as I said, we have no great authorship to go with Asian art, so it is a real problem when you're collecting," she said.

Dr Galloway said while most major collecting institutions were on notice of the prevalence of art smuggling or forgeries, there was only so far the checking process could go.

"Most [galleries] don't [sue], and I think it is probably a good indication that the gallery was very diligent in what it went through, so where do you then have to check the authenticity of documents and how far back can you go?" she said.

"I think it's actually sending a very clear message to the dealers that they have to be a little bit more judicious in their own investigations.

''I think most of the major galleries are well and truly aware of these sorts of issues but it is sending a very clear message to the people who are responsible for creating a lot of this false paperwork."

The convener of museum studies at the ANU school of archaeology and anthropology, Sharon Peoples, said it was not surprising that stolen items were showing up in collections of Asian art, as there had historically been more of a focus in the art world on European art.

This was mainly due to the recent discoveries of art collections that had been looted by the Nazis during the Second World War.

She said art smuggling was also becoming ever more sophisticated, and that the case of the National Gallery would put other major collecting institutions on notice.

"It will hit the international news in the art world," she said.

Dr Galloway agreed. "I'm sure people who have purchased works from this dealer are rather anxiously checking, because there's no suggestion that everything this dealer has sold has not been of good provenance but clearly a number of items have had issues."

A spokesman for the gallery said it was unable to comment on the matter as it was before the court.