A koala habitat has been placed on sale in an online auction by the Baird government in a move community groups say is aimed at limiting public opposition.

Seven lots totalling more than six hectares that abut the Port Stephens-Great Lake Marine Park Sanctuary Zone will be open for bids for four days from Monday.

Koalas are known to head to the nearby sands for a salt lick every spring, a route locals say will be cut off if the forest is sold off for development.

The land sale poses an "unacceptable risk" of development to an area classified as being of high environmental and indigenous heritage value by the government, Port Stephens Council said.