A secret operation by specialist firefighters has saved the world's last stand of Wollemi Pine, a pre-historic species known as "dinosaur trees", from Australia's unprecedented bushfires, officials said. 

Fewer than 200 of the trees exist in the wild, hidden in a gorge in the World Heritage Blue Mountains northwest of Sydney, which have been hit by one of the biggest bushfires that has been ravaging much of Australia for months. 

With flames approaching the area late last year, firefighters deployed air tankers to drop fire retardant in a protective ring around the trees while specialist firefighters were winched down into the gorge to set up an irrigation system to provide moisture for the grove, officials said. 

Matt Kean, environment minister for New South Wales state which encompasses the Blue Mountains, described the operation as "an unprecedented environmental protection mission." While some of the trees were charred by the flames, the grove was saved from the fires, he said in a statement released on Wednesday. 

The pines, which fossil records indicate are more than 200 million years old - pre-dating many dinosaurs - were believed extinct until the Wollemi grove was discovered in 1994. 

Its location has remained a closely-guarded secret to protect the trees from contamination by visitors.

"Illegal visitation remains a significant threat to the Wollemi Pine's survival in the wild due to the risk of trampling regenerating plants and introducing diseases which could devastate the remaining populations and their recovery," Kean said. 

The trees have been propagated and distributed to botanic gardens around the world to preserve the species, but the Wollemi gorge is the only wild stand. 

Australia's wildfires have since October claimed 28 lives, destroyed more than 2,000 homes and burned 10 million hectares (100,000 square kilometers) of land - an area larger than South Korea or Portugal.

About one billion animals may have died in the fires which have driven many species closer to extinction, according to environmental groups. 

The country was enjoying a long-awaited respite on Thursday as rainstorms blanketed much of Australia's east, though a return to warm and dry weather was forecast for later in the southern summer.

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