"The matter is under investigation," a spokesman said when asked about the closure of parts of the Port Authority Bus Terminal.
The white powder was found in a walkway underneath the Port Authority bus terminal entrance at 40th Street and 8th Avenue, according to the police and the Port Authority of New York and New Jersey.
The bus station remained closed for about a half an hour as police conducted their investigation.
The Port Authority later said in a statement that the substance was deemed non-hazardous and that there was no immediate danger at the bus terminal.
The 8th Avenue entrance to the bus station has now reopened and is fully operational following the earlier police activity, the Port Authority added in a Twitter statement.