Cristobal Pera, editorial director of Penguin Random House Mexico, said that Garcia Marquez's family has not yet decided whether to allow the book to come out posthumously, or which publishing house would get the rights. Garcia Marquez died at his Mexico City home on April 17.
The manuscript has a working title of "We'll See Each Other in August," ("En Agosto Nos Vemos").
An excerpt of the manuscript published in Spain's La Vanguardia newspaper contains what appears to be an opening chapter, describing a trip taken by a 50-ish married woman who visits her mother's grave on a tropical island every year. In the chapter, she has an affair with a man of about the same age at the hotel where she stays.
The erotic tone of the work is heightened by the island's tropical charm, with deftly drawn touches of the heat, the landscape, music, and local inhabitants.
The manuscript apparently dates to about the time Garcia Marquez was writing his last novel, "Memories of my Melancholy Whores," which was published in 2004, and deals with similar themes of forms of love; Garcia Marquez, beset by a failing memory, apparently did not write much in recent years.
"'I'm not going to write anymore," Mexican writer Homero Aridjis recalls Garcia Marquez telling him in 2005.
Garcia Marquez biographer Gerald Martin said the manuscript apparently started as a short story.
"This has come as a surprise to me. The last time I talked to Gabo about this story it was a stand-alone which he was going to include in a book with three similar but independent stories," Martin said.
"Now they're talking about a series of episodes in which the woman turns up and has a different adventure each year," he wrote in an email. "Obviously it makes sense and presumably Gabo really did play with it, presumably some years ago."
In Bogota, Colombian President Juan Manuel Santos presided Tuesday over a tribute held in Garcia Marquez's honor.
The Bogota Symphony Orchestra performed Mozart's "Requiem" in the capital's colonial-era cathedral, which was festooned with thousands of roses in yellow, the author's favorite color.
The ceremony also included a performance of the accordion-heavy vallenato music Garcia Marquez loved and which accompanied him in 1982 when he was awarded in Stockholm the Nobel prize for literature.
Around Colombia, a marathon public reading of Garcia Marquez's "No one writes to the Colonel" is planned Wednesday at 1,400 public libraries. The Culture Ministry has distributed 12,000 copies of the book for the occasion.
Colombia's government will also unveil at a book fair next week details of a $100,000 literary prize bearing the author's name that will annually honor the best short story written in Spanish.
In Cuba, the state news agency Prensa Latina announced that this year's Havana Film Festival will be dedicated to the author.
Garcia Marquez was a longtime friend of former leader Fidel Castro and also a major backer of Cuba's marquee international cinema bash, held every December. Festival official Ivan Giroud says Garcia Marquez's family was told of the decision to honor him.
Fidel Castro, now retired, sent a floral offering to Mexico City's Palacio de Bellas Artes, where a ceremony was held Monday night in the writer's honor.
Cuban state television broadcast images Tuesday of the white-and-yellow-flowered arrangement. "To a dear friend," read a silk sash.
Castro, who is largely out of sight in recent years, has not commented publicly on his Garcia Marquez's passing.
AP Writers Frank Bajak in Lima, Peru, Mark Stevenson in Mexico City, Andrea Rodriguez in Havana, and Joshua Goodman in Bogota contributed to this report.