An Adelaide private hospital is running on emergency power after a contractor cut an underground cable.

SA Power Networks said Flinders Private Hospital at Bedford Park in the southern suburbs was forced to switch to its generator because of the cable mishap.

Some intensive care patients are being moved next door to Flinders Medical Centre (FMC), the public hospital.

SA Power Networks said the outage was affecting 223 customers.

FMC lost power when there was a statewide blackout last year, leading to the loss of embryos at its fertility clinic.