At stake is millions of dollars worth of gas, the possible early closure of the Methanex Taranaki methanol plants, and perhaps the delaying of some of the planned new gas-fired power stations.
The parties involved are the Maui partners, the Shell and Todd petroleum mining companies, the Government and the big three gas users, Methanex, Natural Gas Corporation and Contact Energy.
Each party will have its own agenda regarding what it stands to gain or lose from any redetermination of the amount of available gas in the Maui field, this country's largest single energy resource.
Field owner Maui Development Ltd, in which Shell New Zealand holds a 87.5% interest, shocked the energy industry late last year when it announced the results of a detailed reservoir study of Maui.
The study showed the size of Maui was about 285PJ smaller than originally thought and that the field could finish producing as early as mid-2007 and not the contracted year of 2009.
Shell New Zealand chairman Lloyd Taylor earlier this week said he was not confident of a speedy resolution.
"Until the meeting occurs and we know what the views of the Crown and the gas users are in terms of the reserves, how do they see it in terms of the figure Maui Development has tabled, then we do not know the way forward.
"If they agree then it's a relatively straightforward mechanical exercise, but if they disagree then we start to move down the independent expert approach that could take nine months or more to reach a conclusion.
"So it's the definitive meeting, that is, the tabling of views of what the reserves are. Until that occurs we do not know if we are looking at a relatively straightforward process or the more complicated path of independent expert assessment and determination.
"There's a lot at stake here, pretty high stakes poker game, with people playing their cards pretty close to their chests. So I would not be surprised if not all the cards are shown. We are prepared to show our hand, but I don't think the other parties will be so candid."
Taylor believes the next few months will be critical regarding the redetermination path that is chosen, given the various legal, commercial and contractual criteria of the parties. "I have to say that inevitably, with the different commercial drivers' the parties have, I will be very surprised if it goes down the mechanical redetermination path."
Each of the three different sectors - the Maui field owners; the Crown, which charges an energy resources levy and takes a margin for "onselling" Maui gas; and the end users - has to agree and progress can only be made if there is unanimous agreement.
There is also the added complication of the Maui White Paper legislation, which was written about 30 years ago using legal terms of that time.
Taylor says the Shell preference is the simple, straightforward mechanical approach. "So we can settle quickly and move on to the bigger issue of long term security of gas supply for New Zealand, that is, let's develop Pohokura (the large gas field off north Taranaki), free from all these distractions."
