The staff will work in a newly constructed kitchen in Ocado's Hatfield HQ and prepare cuts to order. As well as weight, customers can specify the thickness of a slice or if they want fish skinned and boned.
The new service would enable Ocado to compete with rivals, such as Waitrose and Morrisons, that play heavily on their in-store preparation.
"Our kitchen facilities are state of the art and we have brought new skills to our growing workforce. Ocado's progress has been driven largely by technology but the service counter adds a human touch," said Ocado head of retail Jon Rudoe. "It has been a highly requested service. We do things based on the size of the prize, the ease of doing them and then work them out in a sensible order."
The products include Aberdeen Angus brisket, fillet and topside, as well as lamb and pork cuts. Customers can also buy cuts of offal and fish including Dover sole, monkfish and mackerel.
The meat and fish will be sourced through the Waitrose supply chain but all preparation such as scaling fish will be done by the Ocado team on site.
Waitrose Deliver also offers cuts of meat and fish from store counters, but Ocado claimed some of the products, such as fish from the North Sea, would arrive more quickly to the Ocado HQ than to Waitrose stores, and would therefore be fresher for customers ordering from Ocado.
The service was launched this week and from January will become available on the Ocado iPhone app.