A long-unseen Frida Kahlo painting of a pre-Hispanic idol goes on sale next month at Christie's when it will reappear in public for the first time in 72 years, the auction house said.

Survivor, which sold in 1938 at a New York gallery, has since remained out of sight, its image unpublished, before submission this year for auction at Christie's Latin American art sale on May 26.

"Just when you think everything has been said and done on Kahlo, you come upon this treasure, which really has never changed hands, staying with the same family," said Christie's Latin American art chief Virgilio Garza.

Survivor is one of the few Kahlo paintings to focus on a pre-Columbian idol, he said. It shows a standing warrior figure, mottled brown, with a white headdress. The idol stands on a field with an abandoned house on a ridge, set against a sky churning with blacks, blues, greys and yellows.

Art historian Salomon Grimberg says the warrior symbolises Kahlo's resilience for surviving a tumultuous personal life.

At the time, Kahlo was separated from Diego Rivera, another top Mexican painter and waiting for a divorce, according to Christie's. She had discovered his affair with her sister.