More operations at Auckland hospitals may have to be postponed on Thursday as workers try to fix emergency generators.
The back-up generators at Auckland City and Starship hospitals failed on Wednesday morning during routine six-monthly testing.
Auckland District Health Board spokesperson Mark Fenwick says the source of the problem is not known.
Technicians are working at the buildings and both are still operating normally with mains power.
Fifty-six elective procedures were postponed on Wednesday.
