The concern came from Otago Chamber of Commerce president Ali Copeman as the Dunedin City Council again called for answers from its lines company, Aurora Energy Ltd, yesterday.
The city's street lights failed to fire on Tuesday night, for the fourth time in less than two months, following similar outages on September 16 and 24 and October 20.
The cause of the latest fault has been traced to out-of-date system software used to help control Aurora's lines network, which supplied power to the city's street lights.
Aurora spokesman Gary Johnson said the fault was not related to previous outages, but had since been fixed.
The company's procedures had also been overhauled, including additional checks to ensure software was up-to-date and confirm street lights came on as expected in future, he said.
Mrs Copeman told the Otago Daily Times yesterday the evening outages had not yet affected Dunedin businesses, most of which were closed by the time the lights were due to come on.
Despite that, the blackouts could raise safety concerns for late-night workers travelling to or from their jobs and vehicles later at night, she said.
It also raised the spectre of bigger problems, like those experienced in Auckland, if the blackouts got worse, she warned.
''If it became a full power issue for the city, then I think we would have issues that we'd be looking at.
''Considering it's just street lighting at the moment, as long as they can contain it and work on the infrastructure, then we'll be happy.''
Dunedin Mayor Dave Cull was also concerned Dunedin appeared to be following in the footsteps of Auckland, where major power outages had caused headaches.
''Once in a while is fine, but if it's repeating itself then clearly we need to look a bit deeper.
''I'd like them to get to the bottom of it and prevent it.''
Council chief executive Dr Sue Bidrose agreed, saying the repeat blackouts were ''not what we want to have happen''.
''It's not ideal. It's worse than not ideal.''
''I'm not willing to have a guess.''
However, council roading maintenance engineer Peter Standring said the age of the network had been discussed during a ''good meeting'' with Aurora's representatives following the third outage.
Aurora's representatives had conceded some of the infrastructure was getting old, ''but that's no reason for it to be failing'', Mr Standring said.
Aurora staff would report to council staff on the string of outages within the next week, including the reasons for the latest failure, Mr Standring said.
''As much as they've been able to explain them to us, you do have to draw some conclusions yourself. A bundle of four ... it does raise questions.
''As much as they have explained ... is it something overall that's happening here?''Aurora unveiled plans for a $139 million, five-year network upgrade in Dunedin and Central Otago earlier this year, including replacement of key pieces of ageing infrastructure.
Mr Johnson said, despite that, the string of outages was not related to the age of the network, and electricity supply had been available at all times.
''The overall reliability of the street lighting system is close to 100%. The recent faults are unrelated and have all been fixed.''
