The Wellington-based commission on Thursday said that since Shell and OMV informed it last April of the parties’ decision to market Pohokura gas separately, revocation of joint marketing authority had been an option.

“On the face of it, this represented a material change in the circumstances around which the commission determined to authorise the proposed anti-competitive arrangement, and on this basis, the commission is considering a possible revocation of its decision,” said commission chair Paula Rebstock.

The commission granted authorisation in September 2003 for OMV New Zealand, Shell Exploration New Zealand and Shell (Petroleum Mining) Company, and Todd (Petroleum Mining Company) to discuss and agree on all relevant terms and conditions, including price, quantity, rate, specification and liability for the joint sale of gas from the Pohokura natural gas field.

The authorisation also provided for parties to negotiate and enter into contracts for the sale of gas from the field jointly, for example as one seller.

After two years of saying they couldn’t live without each other, the partners announced in April that they were going their separate ways regarding marketing and selling their shares of Pohokura gas.

Just a month later OMV and Contact Energy announced they had agreed terms for Contact to buy OMV’s 26% share of Pohokura gas for the first five years of production from mid-2006.

Shell then announced sales to Contact, Genesis Energy, NGC and Multigas, while Todd said it would also be selling its share to Genesis.

Ms Rebstock added that the commission was now inviting interested parties to make submissions on whether revocation was appropriate, with the deadline for submissions being October 18.