Southern Clams and the New Zealand Bluff Oyster Company want to transfer 1.5 million, 2-year-old farmed oysters from Bluff Harbour in 2014 and re-lay them in baskets in ''certified growing areas'' in Otago Harbour for up to four weeks.
They would then be harvested and processed at Southern Clams' Dunedin factory for top-end domestic and export markets.
Southern Clams managing director Roger Belton said it was a solution to the poor water quality in Bluff Harbour, which did not meet food safety standards, meaning no shellfish could be taken for direct sale.
After about two weeks in the ''certified water'' of Otago Harbour, the gut contents of the bivalves would be purged of any undesirable bacteria and would be safe to eat, he said.
A trial last year showed four of five batches of oysters were compliant when they arrived in Dunedin.
Southern Clams was seeking a resource consent from the Otago Regional Council for the project and for extra space to place the oyster lines in deeper water in Otago Harbour.
Twenty to 25ha was required, although less than 5ha would be used at any one time. Another sanitation survey would be done to extend the ''certified area''.
The baskets would remain underwater and the only indication of them would be flotation buoys on the surface. All the gear would be removed in the period December to February.
The venture would increase Southern Clams' workload by 30% and increase employment, Mr Belton said. Bluff Oyster Company director Lindsey Topp said the project provided more than just a cost-effective solution to meeting food safety standards.
''Our company specialises in hatching spat and growing oysters. Southern Clams brings to this their expertise in handling and processing live shellfish, plus their brand and position in export markets.''
Mr Belton said a six-month consultation period with harbour users was planned to start straight away. He expected some opposition or concern from the boating community, iwi and others.