New Zealand author Eleanor Catton won the 2013 Man Booker prize for English fiction on Tuesday for her novel "The Luminaries", to become the youngest winner in the award's 45-year history.

The 28-year-old novelist poked fun at the size of her 848-page tome about the 19th century New Zealand gold rush and thanked British publishers Granta for their patience.

"I've actually just had to buy a new handbag because my old handbag wasn't big enough to fit my book," Catton told journalists at a hasty press conference.

Chair of judges Robert Macfarlane described Catton's second novel, set in the New Zealand goldfields of 1866, as dazzling and very clever.

"'The Luminaries' is a magnificent novel: awesome in its structural complexity; addictive in its story-telling; and magical in its conjuring of a world of greed and gold," he said.

Catton's story tells the tale of Walter Moody, who arrives in the goldfields to seek his fortune and immediately stumbles across a tense gathering of local men, who have met in secret to discuss a series of unsolved crimes.

A wealthy man has vanished, a whore has tried to end her life, and an enormous fortune has been discovered in the home of a luckless drunk.

Moody is soon drawn into the mystery: a network of fates and fortunes that is as complex and exquisitely patterned as the night sky.

Catton said she was grateful to her publishers for allowing her the freedom to explore her theme without pressure to make an obviously commercial novel.

"I was free throughout to concern myself with questions not of value, but of worth," she said after accepting the award from Prince Charles's wife, Camilla, the Duchess of Cornwall, at a glittering dinner in London's ancient Guildhall.

COMMONWEALTH

The other shortlisted authors for the prize were Canadian Ruth Ozeki for "A Tale for the Time Being", Indian-American Jhumpa Lahiri for "The Lowland", Zimbabwean NoViolet Bulawayo for "We Need New Names", Briton Jim Crace for "Harvest" and Irish writer Colm Toibin for "The Testament of Mary".

The win by a Commonwealth author and the second from New Zealand in the Man Booker's history is likely to set literary tongues wagging over the decision by the prestigious prize's organizers to change the rules for eligibility from 2014.

In September, the Man Booker said it will permit authors from all over the world to compete for a prize that had been previously exclusive to writers from the United Kingdom, Ireland and the Commonwealth.

The decision caused a ruckus in the publishing world. Some British authors fretted that the American publishing juggernaut will drown out the voices of lesser known Commonwealth novelists such as Catton, Bulawayo and Ozeki.

"Will a young woman published in New Zealand stand much of a chance again?" Crace said after the dinner.

However, Catton said she was glad that the changes removed the artificial restrictions of nationality from the prize, echoing assertions from Man Booker organizers that the award will become the world's biggest English-language fiction award.

"I think it's a really great thing that finally we've got a prize that is an English-language prize that doesn't make a distinction for writers who are writing from a particular country," she said.