The Turnbull government has rejected a plan to expand the phosphate mine on Christmas Island "because it is likely to have significant and unacceptable impacts on matters protected under national environment law".

Christmas Island is home to 254 species that exist nowhere else in the world including the famous red crabs, rare seabirds like the endangered Abbot's Booby, and even endangered plants like the endangered cave fern.

"The government's decision reflects the fact that Christmas Island is a unique and irreplaceable environment," said Environment Minister Josh Frydenberg.  "The island was uninhabited until the late 19th century, which allowed many species to evolve without human interference.

"There is also a very real threat that this pattern of clearing would allow the introduction of aggressive weed species with the capacity to overwhelm native vegetation and to alter the structure of the surrounding forest," Mr. Frydenberg continued.  "Environmental damage on small islands has a far greater impact because of its limited capacity to recover from declines in biodiversity caused by the cumulative effects of land clearing," he said.

Phosphate Resources Limited wanted to clear 6.83 hectares of land and undertake exploration drilling in search for additional phosphate resources on Christmas Island.  The local shire agreed with the plan, and fears that as many as 250 jobs could be lost without the expansion.