Dunedin man Rob Donaldson was in Christchurch to support his 61-year-old wife, who lives there, as she underwent surgery for bowel cancer on March 6.
Mr Donaldson told the Otago Daily Times his wife had been released from hospital on Tuesday and returned to her St Albans flat, but woke up on Wednesday in pain which grew worse through the morning.
At 10.15am, their daughter phoned St John for help and was told someone would be there within 10 minutes.
"Ten minutes became 20 minutes, became half an hour, and we waited.
"She was not feeling well at all - she was in an awful lot of pain. It was getting worse," Mr Donaldson said.
More than an hour later, when an ambulance had not arrived by 11.25am, Mr Donaldson put his wife in his car and drove her back to Christchurch Hospital's emergency department himself.
When he arrived at the hospital, there were "six ambulances sitting there", he said.
Mr Donaldson had since lodged a complaint with St John and was phoned yesterday by an "apologetic" staff member, who explained an ambulance was dispatched at 11.20am but then diverted to an emergency call.
"I'm so annoyed with St John. Very annoyed," he said.
"I'm not a medical person, but I would have thought St John would at least turn up to assess the situation."
Contacted for comment, St John Christchurch metro territory manager Craig Downing said "any delay was not ideal".
"St John takes patient safety very seriously ... We apologise to Mr Donaldson for any distress caused to him and his wife.
"We are currently looking into Mr Donaldson's concerns."
