The main welding of the Maui gas pipeline has been done and Vector hopes customers still cut off should have it restored by late Sunday.
A major leak discovered on the 307km pipeline meant thousands of Taranaki businesses were ordered to stop using gas, forcing them to shut up shop.
The leak was due to a crack near a curve on the pipe.
Maui pipeline operator Vector chief executive Simon Mackenzie says the crack could have arisen because of land movement.
Large industrial users and electricity generators still have their supply off, says Maui pipeline incident spokeswoman Sandy Hodge.
Customers who have had supply restored using Vector's pipeline are those of Band 4, which includes medium to large businesses; Band 5, which includes cafes and small businesses; and Band 6, which includes essential services such as hospitals.
Ms Hodge says residential users have been able to maintain their supply the whole time using Vector's pipeline.
The main welding of the pipe and the first stage of weld testing have been completed.
Vector is required to wait 24 hours before doing any further testing of the weld pipes, which is necessary for certification.
Ms Hodge says depending on certification, supply should be restored to those who are still cut-off by late Sunday.
"We remind customers that are without gas supply, primarily large industrial and electricity generators, that they are not to use gas until they are advised by their retailer," she says.
NZN