Urgent search on for missing mother Stephanie Castellanos, 28, who has 'recently given birth' and went missing from Regent Street, Dee Why

A public appeal has been made to help locate a missing woman who has recently given birth.

Stephanie Castellanos, aged 28, was last seen on Regent Street at Dee Why on Sydney's Northern Beaches about 11.10pm Friday. 

When she was not able to be located, police were notified who commenced a search for her.

Serious concerns are held for the welfare of Ms Castellanos as she requires medical treatment after recently giving] birth. 

She is described as white, about 175cm tall, with long brown hair, brown eyes and a slim build.

She was last seen wearing a blue t-shirt, black pants, and socks.

Anyone with information is asked to contact Northern Beaches Police or Crime Stoppers on 1800 333 000.