The magnitude 6.6 earthquake which struck near Seddon last week hit the Lake Grassmere salt farm and refinery hard.
About 60,000 tonnes of salt is harvested annually at the Lake Grassmere site, south of Blenheim, which is owned by Dominion Sat.
Chief executive Shane Dufaur said while the biggest earthquake was centred directly below Lake Grassmere, the company got off lightly compared with the townships of Seddon and Ward.
"Essentially, there's no damage to the walls and the lake proper itself," Mr Dufaur said.
"I think where the major issues are is in the plant itself, and most of that is pretty superficial. It's ducting, it's pipework that needs to be built."
The main transformer had moved on its feet but that had been secured, he said.
Dominion Salt would be able to meet demand from its customers through supplies at its Bay of Plenty refinery, Mr Dufaur said.
He expected the plant to be back up and running in two to three weeks.