A woman will face court tomorrow after an alleged armed robbery in Sydney this morning.

About 4am (Sunday 1 November 2015), a 16-year-old girl was with a group of friends when they met with another group near Lincoln Crescent, Woolloomooloo.

When the girl left the area, she was approached from behind and pushed down stairs on Cowper Wharf Road by an unknown woman.

The woman then allegedly threatened her with a knife and demanded cash, before running from the scene with a bank card, a mobile phone and a set of keys.

The girl was not injured.

Police from Kings Cross Local Area Command were contacted and an investigation was commenced.

Shortly after, officers attended a home unit on Brougham Street, Woolloomooloo, and spoke with a group of people.

A 21-year-old Raby woman was arrested and taken to Kings Cross Police Station, where she was charged with robbery while armed.

She has been refused bail to appear at Central Local Court tomorrow (Monday 2 November 2015).

Inquiries are continuing.