SINGAPORE: Call centre lines across institutions under NHG Health were temporarily unavailable on Tuesday (Oct 13).
The National University Hospital (NUH) and Singapore General Hospital (SGH) also said separately that they were experiencing system disruptions.
NHG Health said in a Facebook post that it was working to restore access to the call centre lines.
Four hospitals are under NHG Health: Tan Tock Seng Hospital, Khoo Teck Puat Hospital, Woodlands Hospital and Yishun Community Hospital.
The group also manages 10 polyclinics, including Ang Mo Kio Polyclinic and Yishun Polyclinic, and institutions such as the Institute of Mental Health, National Skin Centre and National Centre for Infectious Diseases.
CNA's calls to NHG's main contact centre hotline at 10am immediately failed before connecting.
Calls to Tan Tock Seng Hospital and Khoo Teck Puat Hospital also failed to connect, though a call to the Institute of Mental Health connected successfully.
Tan Tock Seng Hospital said in a Facebook post that patients visiting its clinics and pharmacy may experience longer waiting times while the call centre lines are down.
NHG Health said patients and members of the public may visit its websites and the HealthHub and NHG Health app for assistance.
"We are sorry for the inconvenience caused. We seek your understanding and patience during this time," NHG Health said.
Separately, NUH said in a Facebook post that it is "experiencing a system downtime" and that delays were expected for its patients.
"Business continuity measures and downtime processes are in place," NUH said.
"We thank our patients for their patience and understanding as we work to minimise disruption and resume normal operations as soon as possible."
SGH also separately said in a Facebook post that it was experiencing a temporary system disruption.
The system disruption was affecting some of the hospital's services, including outpatient appointment bookings and changes, visitor registration and billing enquiries.
SGH said its call centre remained open but was temporarily unable to process appointment bookings or changes.
Visitor registration could also take longer than usual, so patients should allow for additional time when visiting, SGH said.
"Our teams are working to restore the affected systems as soon as possible and will provide updates when services resume," SGH said.
"We sincerely apologise for the inconvenience and thank you for your patience and understanding."