Lightning strikes have "fried" computers and modems in Westport over the past week.
IT@Work managing director Brent Oldham has been "flat out" fixing and/or replacing about 10 modems and half a dozen computers since the spate of storms began last Friday.
"Once lighting gets through, that's it."
Sometimes it was just the power supply blew - an easy and "cheap-ish" fix.
Repairs cost around $200, so in many cases it wasn't worth claiming insurance.
It's usually the modem that goes first. Sometimes it blows through to the computer that's hooked up to it.
"Most of it is under people's excess."
Other damage was more serious, he said. Some people had brought in computers with fried motherboards (the main circuit board).
"It's usually the modem that goes first. Sometimes it blows through to the computer that's hooked up to it."
Laptop motherboards were particularly expensive to replace. Some can cost up to $500. ADSL modems cost around $90.
Some people whose modems "blew up" on Monday lost another one two days later, Mr Oldham said. He encouraged people to err on the side of caution, and unplug their modems from the power supply and telephone jack while lightning was about, or while they were not using the internet.
"If it looks like it's going to be a rough night, pull it out before you go to bed."
Lightning storms blew through every year, but the cluster of storms over the past week had been "particularly nasty", he said.
"People get worried about it coming through their power sockets. It's generally not -- 99.9 per cent of the time it's coming through the phone circuits."
However, a big lightning strike on Monday night hit "right over town".
"That must have come through power circuits because we've got people that use wireless internet connections who lost gear. Power adapters melted."
If lightning struck the ground, it travelled through underground cables sitting in groundwater, he said.
"It just blows right through. In that situation there's really not much you can do."
Buller Refrigeration and Electrical owner Kevin Jackson was called to a couple of commercial jobs on Tuesday, after lightning the night before. A series of power cuts caused electrical surges, which created problems for two local businesses.
One surge happened while his firm was at one of the premises doing other electrical work, he said.
"Suddenly everything started going bang."
The problems caused by the surges weren't too expensive to fix.
"It's probably no more than $1000 worth of repair."