Wrexham Maelor Hospital was surrounded by emergency service vehicles for much of the afternoon today.
Nobody was allowed in or out of the hospital in North Wales from around 2pm and patients were being warned to stay away for at least the next two hours after reports of a package being found.
Dozens of police cars were pictured blocking off access to the hospital, which is in the outskirts of Wrexham.
The Betsi Cadwaladr University Health Board confirmed in a statement soon before 5pm that a package had been reported, and North Wales Police said it was seemingly a hoax call that was responsible.
A statement from the health board said: "A search of the Wrexham Maelor was carried out following reports of a suspicious package. We have worked with North Wales Police to carry out a search, which has now been completed. Access to the hospital is no longer restricted and we would like to apologise for any inconvenience caused."
CI Mark Williams of North Wales Police said: "I would like to thank staff, patients and the public for their cooperation and patience following what appears to have been a hoax call to Wrexham Maelor Hospital.
"Our priority throughout this afternoon’s incident was to ensure people were kept safe."
The incident began as Labour leader Sir Keir Starmer was visiting the nearby Wrexham Lager brewery accompanied by the First Minister Mark Drakeford.
The hospital is well-used by people in the Oswestry and North Shropshire areas as well as being the main hospital and accident and emergency department for Chirk and the Ceiriog Valley.
An earlier statement from the trust said: "Due to an ongoing incident at Wrexham Maelor Hospital that is being managed by North Wales Police we are asking people not to attend their planned appointments today and to avoid the site.
"We would like to apologise for any inconvenience."
One nearby resident said: "There are helicopters up in the air and roads leading to the hospital are closed off."
Chirk councillor on Wrexham's unitary authority, Gareth Baines, said: "Maelor Hospital is currently on 'lockdown' due to an ongoing incident at the site, with nobody allowed in or out of the hospital. Please avoid the Croesnewydd area."