A "couple" of bidders are even flying to Auckland for next Tuesday's auction.
"This auction is looking to be something special and certainly the interest in quality Indian modern art is strong, even in Auckland," Mr Grigg said.
"These works are difficult to get hold of and are becoming increasingly popular."
Bombay-born Khakhar wowed the art world with early works that mashed deities from kitsch posters with street culture and graffiti.
He was courted for major international exhibitions and even held a solo show at the most famous museum of modern art, the Pompidou Centre in Paris.
Although the self-taught artist and former accountant died in 2003, aged 69, his art continued to hang in some of the world's top galleries and fetch six figures at international auction houses.
Who is Bhupen Khakhar?
• A former accountant and self-taught painter, Bhupen Khakhar is hailed as India's father of Pop Art.
• He was inspired by French Post-Impressionist painter Henri Rousseau, English painter David Hockney, and Italian Renaissance style.
• Works often sell at auction for six figures. Oil on canvas, Waiting for Darshan went under the hammer at Christie's New York last year with an estimate of NZ$630,000-NZ$950,000.
• Midnight's Children author Salman Rushdie was a close friend.