The 78-year-old, perhaps best known for leading the Art Gallery of NSW for more than three decades, died on Sunday.

"Edmund's contribution to the visual arts, and to museum practice in Australia, is inestimable," Arts Minister Mitch Fifield said on Monday.

"Describing himself as a student of life, art, civilisation and the humanities, the often flamboyant and sometimes irreverent Edmund Capon has left a lasting impression on Australia's cultural landscape."

Capon was appointed director of the NSW gallery in 1978, for a three-year term.

In 2011 - after 33 years in the role - he retired.

Senator Fifield said the internationally-trained art historian's knowledge, passion and commitment turned the gallery into a renowned showcase for art.

He doubled attendance at the gallery within a decade of being at the helm, oversaw two building expansions, established an acquisitions foundation, undertook significant collection development and curated many important exhibitions.

Australian Associated Press