A major outage on the West Coast left thousands without power for two hours.

Westpower General Manager Generation and Technology Rodger Griffiths said Transpower has identified a 110kV bus fault at the Kikiwa substation near Nelson.

He said it was due to "too much load at the time."

A Transpower spokesperson confirmed they had restored power to the affected areas at 11am.

Power has been restored to their sub-stations but it is up to the line companies to restore it to consumers.

The spokesperson said they expect most, if not all, affected residents should have power now

Griffiths confirmed power in Greymouth and the South Westland area had been restored at 10.40am.

Hits presenter Dave Nicholas said he is on holiday staying at a bach in Fox River, between Greymouth and Westport.

"I was just chilling out, going with the flow of the morning and then everything went dark.

"It's a little bit frustrating, I'm already in a primitive area as it is. The electricity was quite a bonus, quite a luxury, but now it's not there anymore," he said.

Nicholas said it is concerning that the two major lines on the West Coast can go down "like this."

"It leaves the region sort of hanging by a thread. A little bit concerning, I don't know how often this happens.

"As for making the morning coffee number two, I'm not sure how that's going to happen. Might just have to wait that out."

Greymouth chief fire officer Lee Swinburn earlier told the Herald they lost power at about 9.30am.

"We understand it is a Transpower issue, things have come to a bit of a grinding halt," he said.

He said he has had a few calls from business owners who require power to run their fire protection systems.