A MANHATTAN ad executive on a first date fell 17 storeys to her death after going outside to have a cigarette on her balcony.

New York City police say Jennifer Rosoff, 35, was with a man she had been on a date with outside her corner apartment on the 17th floor in midtown Manhattan shortly before 1am on Thursday (3pm AEST) when she either leaned against or sat on the railing.

"You know, you shouldn't do that," her companion said, according to sources who spoke to dnainfo.com.

"I do it all the time," she replied moments before the railing collapsed.

Sources told The New York Post that the date, who lives nearby, heard two sharp pops before the railing collapsed and his girlfriend of a single night flew backward off the tiny balcony, screaming as she fell.

Police believe it gave way and she fell, landing on construction scaffolding at ground level at the 400 East 57th Street apartment. When paramedics arrived, she was motionless and not breathing and was pronounced dead at the scene.

"I heard the thud last night," said neighbor Sara Shubert, who has lived at 400 E. 57 for eight years.

"I heard from my friend that she saw a man come out of the main lobby elevator frantic, and screaming, 'My friend fell! She fell off the building'."

A neighbour from the 14th floor heard Rosoff shriek past his window.

"I heard a scream and I came out of my apartment last night," said the neighbour, who asked not to be named.

The neighbour ran out into his hallway, where he found the date, devastated.

"There was a man who was hysterical and crying by the elevators. He told me that he and Jennifer were on their first date," the neighbour told The Post.

"They had just gotten back and she was showing him her apartment. Then he said they stepped out onto the balcony and had a drink. She was sitting on the balcony, then the railing gave way and just snapped."

The medical examiner will determine a cause of death.

Ms Rosoff's death was met with shock by her advertising colleagues.

"I was meeting someone for coffee today and the second they got off the elevator and they said: 'I had the worst e-mail. The subject was Jenn Rosoff died,'" said a friend in the ad sales industry who requested anonymity from The New York Times because he did not want to be seen as inserting his name into a tragic situation.

"I hate in situations like this when people want to bury saints, but she was a great person,” he said.

Ms Rosoff had worked at Lucky magazine and The New Yorker, and was currently at a social media start-up called TripleLift.

TripleLift chief executive Eric Berry said in a statement that Ms Rosoff was "a well-loved and highly-respected member of our team."

"Her tremendous energy and humour brought so much joy to the office," he said.

The city's buildings department was at the scene on Wednesday examining the railing. A photo of the balcony shows part of it bent down in a V-shape.

Originally published as Woman plunges to death on first date