Staff believe several people may have been involved in stealing an emu from a Sydney wildlife park.

There are also concerns for the welfare of the bird, which is likely to be "extremely stressed" by the ordeal of being taken from its home and forced over fences by its captors.

A large amount of feathers was all that remained in the adult female's enclosure at Featherdale Wildlife Park on Tuesday morning when she was noticed missing.

Police believe she was stolen between 4.50pm on Monday (AEDT) and 7.20am on Tuesday (AEDT).

Senior Park Curator Chad Staples said the size of the yard and nature of the bird led staff to believe there were several people behind the theft.