The benevolent Vishnu is all about defeating the forces of chaos and restoring harmony in the universe.

So in an era of global omnishambles, a major exhibition devoted to the Hindu deity couldn't be more timely.

"Vishnu is supposed to reappear at moments of crisis," said co-curator Associate Professor Chaitanya Sambrani.

"This might be quite a good time for him to make an appearance."

Avatar: Forms of Vishnu at the Art Gallery of New South Wales is the first Australian exhibition devoted to Vishnu, and the gallery's biggest display of South and Southeast Asian art in more than two decades.

Vishnu has endless forms, but there are 10 main avatars, including the hero of the Ramayana epic Prince Rāma, and the spiritual guide Krishna.

He can also appear on earth as a fish, a tortoise, a boar, part man part lion, or a man with the head of a horse.

With so many possibilities, you'd think Vishnu might be hard to spot, but there are often clues: he could be holding a discus, a conch, a mace, or a lotus flower in his four arms.

Oh, and he's frequently depicted with blue skin.

The many avatars of Vishnu were worshipped by hundreds of millions of people in India and beyond, while artists had long engaged with his mythological narratives, said Dr Sambrani.

It's a fascinating tradition, but one that had never really been explored by art institutions, especially in Australia, he said.

The famed temple complex Angkor Wat in Cambodia, for example, was built in the 12th century and originally dedicated to Vishnu, before becoming a Buddhist shrine.

The earliest work in the exhibition is even older than this, a sixth century Cambodian sculpture of Krishna holding up Mount Govardhan.

There are also some of the earliest paintings created to illustrate the great Indian epics, the Ramayana and Mahabharata.

With more than 200 artworks drawn from collections in India, Cambodia, Britain, Australia and Switzerland, the exhibition also features work by contemporary artists from Australia and India.

For a deity with so many options, Vishnu actually spends most of his time resting in the cosmic ocean, explained the gallery's senior curator of Asian art Melanie Eastburn.

"He descends to earth and takes an avatar when he's really needed, which he is now," she said.

Avatar: Forms of Vishnu is on at the Art Gallery of NSW from Saturday until October.