Arnhem’s main general hospital has had to cancel appointments on Tuesday morning after problems emerged during an update of its computer systems.

The Rijnstate hospital, which also has campuses in Elst and Zevenaar, said all operations and clinical appointments scheduled for before 12 noon would have to be postponed.

A spokesman said the hospital had not been hacked, but staff discovered during a routine network update on Monday night that they were unable to add details to patients’ medical records.

“That makes our records unreliable,” the spokesman told AD.nl. “It affects medication that doctors have prescribed and results of lab tests.”

The hospitals have a total catchment area of 450,000 people, most of whom live in Gelderland.

The hospital had hoped to fix the problem by 10am, but later extended the deadline to noon as technicians continued to work on the network. Emergency procedures and treatment for patients who are already in hospital are not affected.

The spokesman said affected patients would be contacted by telephone to make new appointments. Some patients could not be reached on Tuesday because the records containing their phone numbers were inaccessible.