The Kapuni liquid CO2 plant will build back up to full capacity over the next few months following a safety issue that shut it down in December.
Todd Energy, the plant's owners, says it has identified the root cause of the safety issue and is planning a staged production ramp-up which would see it return to full capacity by the end of the year.
"The first production of liquid CO2 is expected in around two weeks," they said in a statement.
New Zealand is in the midst of a critical shortage of CO2, raising concerns about the impacts on industries from breweries to shipping.
The closure of the Marsden Point refinery at the end of March last year meant the only remaining domestic source of liquid and other food-grade CO2 was Todd Energy's Kapuni gas processing plant in Taranaki.
However, the plant was temporarily closed in 20 December 2022 due to the identification of a potential safety issue.
This exacerbated a shortage that was already raising alarm, particularly in the beverage industry where its use is critical to several stages of production.
"Just before Christmas, our normal operating surveillance detected a risk relating to the release of ammonia from a pressure safety valve at our liquid CO2 plant," says Todd Energy CEO Mark Macfarlane.
"The age of the plant and lack of instrumentation means that it has taken some time to identify the issue, but now that we understand the cause, we can begin implementing solutions to bring the plant back online."
Todd Energy has outlined three stages of increasing supply as it resumes operation.
The first stage will see the plant resume operation under strict operating procedures and only at roughly 30% in around two weeks.
The Kapuni plant will undergo a routine shutdown from late February to mid-March to enable a scheduled inspection, something Macfarlane says was planned since last year and "cannot be moved due to its statutory nature".
Following the shutdown the plan is expected to reach over 50% production capacity from the end of April, and finally return to 100% capacity "once all engineering projects are complete at the end of 2023".