The as-yet unnamed chick at the Taiaroa Head albatross colony was found to be fly-blown on Monday, Otago Peninsula Trust marketing manager Sophie Barker said.
Maggots and eggs were removed, and an antiseptic cream used to clean the area, but earlier today it had dropped below its hatch weight, she said.
Rangers intervened, removing the chick from the nest and placing it in intensive care to try to nurse it through, she said.
Ms Barker said staff were keeping their "fingers crossed'' the unnamed chick would survive.
"Prognosis? Praying,'' she said.
"You become so attached to them. We have watched the egg incubating for about 80 days and then the chick hatching.
"Yesterday there was a beautiful reunion when mum, RBK, came home and saw her chick for the first time.''
In the meantime, the chick's parents had been given a foster chick, which was visible on the Department of Conservation' Royal cam live-streaming service.
The foster chick was moved after having "a problem'' at its own nest, she said.
Moana the chick, which featured on the Royal cam last year, attracted more than 600,000 views on Youtube.
