Alan Witheford, of the Stewart Browne electrical firm, urged Western Bay residents to take extra care with do-it-yourself electrical repairs, as dodgy wiring could result in serious injuries or death.
Mismatched wiring on power points could be a serious hazard for DIY electricians, he said.
"Probably what happens is the powerpoint they buy from Mitre 10 ... is laid out a bit different on the back than the one they take off [the wall].
"They don't know where the wires go and they just take pot luck."
Incorrectly installed light fittings were another common problem, he said.
The Otago University research, which involved about 1600 participants who were injured at home, assessed participants' properties for structural hazards.
A number of houses that lacked insulation were also assessed.
Findings showed nearly two-thirds of homes lacked working smoke alarms and more than half had driveway fences that were unfinished.
Forty-nine per cent of homes had unsafe hot water temperatures (over 60°C) and one-third had access areas that were poorly lit.
Lead author Michael Keall believed the results were "relatively typical" of many New Zealand homes.
Nearly 40 per cent of injuries were related to a home's structural aspect, the findings showed.
Fixing dangerous structural hazards would cost an average of about $600 per household.
"This expenditure is justified in terms of increased safety," he said.
Outdoor areas were important, with 37 per cent of accidents occurring on home paths, steps and in the garden.
Those aged under 5 years and the elderly were most vulnerable.
"One of the more interesting aspects is that people who are injured tend to blame themselves rather than look at hazards around the home that may have played a role," Dr Keall said.
Fixing these hazards was crucial to improving home safety, he said.
Previous research put the total social cost of death and injuries in the home at $13 billion in 2007. In contrast, road injuries and deaths amounted to nearly $4 billion.
Social costs include loss of output due to injury or death, reduced quality of life and medical expenses.
Safety at home
Install handrails for steps, inside and outside
Put high-visibility slip-resistant edgings on steps
Install lighting for outdoor areas
Put slip-resistant surfacing on decks and steps to prevent falls
Regularly check smoke alarms are working
Source: Dr Michael Keall
