Portions of New York's Port Authority Bus Terminal — one of the largest transportation hubs in the United States — have been reopened after an evacuation conducted after police found a non-hazardous "white substance" in a walkway, according to the New York Police Department and the terminal itself.

The terminal was only partially cleared as officials began investigating what was later deemed to be a cleaning agent that spilled, and the terminal reopened by 10.15am, according to New York Pix 11.

One man at the scene said that he went to a Starbucks after police arrived, and that he was told he "might be stuck there for a while".

The crowds were reportedly orderly. No injuries were immediately reported.

Police say that they received a call for a suspicious package just after 9 am, leading to the evacuations.