Five months after proposing a merger, rivals Port Otago and Lyttelton Port of Christchurch (LPC) remain in agreement over the signed "memorandum of understanding" but have delivered no further detail.
The parties said in October they hoped to make more details available by March this year.
However, because of listed-LPC's obligation to make announcements through the stock exchange, Port Otago chairman John Gilks has declined to reveal any details.
"We have to respect Lyttelton's position," he said last week.
Port Otago took a contentious $37 million blocking stake in LPC three years ago and the pair repeatedly said they were not in formal talks.
However, last October they announced they were considering a merger proposal.
At the time, Mr Gilks said if the proposal went ahead there would be one company and one board controlling the operational assets and businesses of both ports.
The key consideration was whether government legislation or Commerce Commission approval would have to be sought, as the scenario would be precedent setting.
Each port would retain ownership of its core physical assets, such as wharves and land, which was recognised by each party as being of significant importance, not only to shareholders but to local interests.
Port Otago is 100%-owned by the Otago Regional Council.
Publicly listed LPC is 75%-owned by the Christchurch City Council, Port Otago owns 15% and the balance by shareholders with stakes of 1% or less.
Gains for the pair would include avoiding duplication through co-ordination of road and rail use, development of new joint services and savings from other, unspecified "efficiencies".
No timeframe, details or options of governance or responsibility have been spelled out.
However, Port Otago may list on the stock exchange, or LPC delist.
