Police investigating a call in which a woman said she had left a baby outside a Citizen's Advice Bureau (CAB) now believe the call was not genuine.
The woman, who had a southern African accent, dialled 999 on Thursday and told the operator she had left the two-week-old outside the CAB in Bury.
Officers searched the area and all CAB branches across Greater Manchester.
Police want to trace the woman, who may need medical help, and urged anyone with information to contact them.
They said the call was made from the Bolton area.
Supt Graeme Openshaw, of Greater Manchester Police, said: "After a large amount of police work we are now convinced this was a hoax call.
"I want to reassure people that we do not believe a baby has been abandoned in these circumstances.
"I cannot speculate on the motive or reasons for anyone making this type of call, but I can tell her that her actions have resulted in hundreds of officer hours being wasted."
He added: "It is quite possible this woman might need medical help in some way, so I would urge anyone with information on who she may be to get in touch with us.
"Not only do we need to prevent this from happening again, but we need to trace this woman to see if any kind of help can be given."