Barnes Wild Bluff Oysters manager Graeme Wright said staff safety concerns had led to processing delays after the company reopened on Monday.
It had now begun to supply supermarket chains and some fish outlets in New Zealand.
"The safety of our staff is our priority, so only half of the team is working each day.
"They are keeping 2m distance between them."
He said the company had been registered as an essential service and was allowed to process oysters under Alert Level 4.
"We are still operating under very limited production as supermarkets are only a small part of our business.
"I think we are operating at about 20% of our capacity."
Mr Wright hoped the number of businesses wanting oysters would increase next week when the country moved to Alert Level 3.
The factory usually supplied takeaway shops and restaurants throughout New Zealand.
This week, the company supplied oysters to Harbour Fish in Dunedin and also had inquiries from takeaway shops in Balclutha and Milton.
Fowler Oysters also resumed processing this week.
Manager Terina Stockwell said the company normally relied heavily on the tourism market.
She said they were exploring options to open their takeaway store next week.
Both companies said they were delivering to customers around the country through couriers.
