The National Gallery of Australia has decided to postpone the Ngura Pulka Epic Country exhibition, which was set to showcase artworks from the APY (Anangu Pitjantjatjara Yankunytjatjara) Lands, due to the need for further investigation into allegations of interference.

The exhibition, titled Ngura Pulka Epic Country, was originally planned to take place from June 3 to October 8.

The gallery has described it as "one of the largest and most significant First Nations community-driven art projects to have ever been developed."

The delay comes in response to allegations published by The Australian newspaper in April, claiming that non-Indigenous workers from the APY Art Centre Collective had painted on artworks created by Aboriginal artists.

The claims, made by a number of Aboriginal painters and supported by incriminating video evidence, have caused widespread controversy surrounding the upcoming Ngura Pulka - Epic Country Exhibition at the National Gallery of Australia.

The collective has vehemently denied the accusations, asserting that they are false and defamatory.

To ensure a thorough investigation, an independent review panel appointed by the NGA requires additional time to complete their assessment.

Copyright lawyers Colin Golvan and Shane Simpson, assisted by First Nations experts Yhonnie Scarce and Professor Maree Meredith, are conducting the review.

They are examining if the 28 paintings in the exhibition were truly created by the attributed artists and to what extent the APY Art Centre Collective's staff contributed.

The gallery has pledged to publicly release the final report.

The NGA is awaiting the results of a second government probe by the Australian, South Australian and Northern territory announced in May, but the time frame for the review is yet to be determined.

The delay of the exhibition leaves the gallery in a difficult position as Ngura Pulka was a key part of their winter program, and there is no news on its replacement.

A statement released on Wednesday said "the National Gallery is committed to continuing to work with APY Lands artists and supporting their ground-breaking work."