A stranger sexually assaulted a woman by a Manhattan pier early Friday, officials said.

The 36-year-old victim had just gotten off work around 3:30 a.m. near Pier 62 and West 23rd Street in Chelsea when a man approached her and asked for a cigarette, cops said.

The stranger then punched her in the face and sexually assaulted her, police said.

She was taken to an area hospital, where she was listed in stable condition, with trauma to the face and neck.

The suspect is described as a heavyset man in his 30s, possibly homeless, officials said.