The company was not immediately available for comment.
The superfast service, dubbed "Amazon Prime Now", attempts to replicate shopping in a physical store by delivering some items in an hour or two, the WSJ report said.
Amazon has been experimenting with three different courier services to pick the fastest and the most careful for its deliveries, the report cited the source as saying.
The bike messengers are paid around $15 an hour and work in eight hour shifts, the Journal reported.
Amazon will use its West 34th Street location as a base for the bike messengers. The company has built a lounge there with facilities including foosball, pool and airhockey tables, for messengers waiting between deliveries, the Journal added.
© Thomson Reuters 2014