Army Technical Officers who were called to the scene said the alert was a hoax.
It followed the discovery of a suspicious object at Derramore Park in Magherafelt, Co Derry
As a result, Derramore Park has been closed between Derramore Court and Derramore Gardens.
A number of people were moved from their houses in Derramore Park and Derramore Drive.
The Meadowbank Sports Arena was made available for residents.
All roads have now re-opened and residents have been allowed back into their homes.
Chief Inspector Andy Lemon has condemned those who left the object.
“This device caused a great deal of local inconvenience, with about 30 people having to be moved from their homes on a bitterly cold day.
“I would ask anyone with information about the incident to contact the detectives at Magherafelt station on the 101 non-emergency number.”