Smaller than the other three potlines at the smelter, the upgraded potline four was officially reopened by Prime Minister Jacinda Ardern in December 2019.
Less than a month ago, Rio Tinto announced that it had terminated its contract with Meridian as part of a plan to wind down operations and close the Tiwai Point smelter in 2021.
The news came months after Rio Tinto had signalled that it would announce the result of a strategic review.
While the news was immediately met with resignation by the Government, this week there were further hints that the decision may not be final.
According to a source, Alf Barrios, the chief executive of Rio Tinto's aluminium business, gave an address to staff at Tiwai Point by videolink this week, during which he indicated the final decision on the future of the smelter would be announced in four to six weeks.
E Tu organiser Joe Gallagher said he was not aware of the decision date, but understood that the "drop dead date" for a decision on the smelter's future was December 31.
"I'd like to think some common sense comes into play before Christmas, and I'd think there's still some room before Christmas to turn it around."