The closure follows the suspension of the company's access into China for its beef products.
OML director Richard Thorp described the shutdown as a "temporary break in production", but wouldn't provide any detail as to how long the plant would be closed.
It was not known if staff would be paid during the shutdown.
He said the company had informed farmer suppliers and was working with the New Zealand and Chinese regulators to address their concerns.
He said there would be a small group of staff retained for some "non-China" processing and the company was arranging network support for the remainder of staff.
Several staff approached by the Otago Daily Times yesterday declined to comment, saying they were not allowed to speak to the media.
However, it appeared to be business as usual yesterday, with at least one truck being loaded by forklift.
It was also unclear yesterday what the "regulatory concerns" were but a spokesman for the Ministry for Primary Industries (MPI) said it was "urgently working with the company and the Chinese authorities to get more information".
The MPI spokesman said the suspension was not related to food safety issues.
"The suspension applies to Oamaru Meats only and does not apply to exports from any other NZ meat establishments that export to China," the spokesman said.
Local livestock agents said they were not aware of the finer detail, only that with the plant in full swing particularly with bobby calves, other processors would "take up the slack", notably Alliance's Pukeuri plant.
Waitaki MP Jacqui Dean said she hoped staff would get every assistance possible from the company to find new jobs. She said the closure would directly impact not only plant workers but farmers needing stock processed at this busy time of year.
"This is sadly reflective of the shaky global climate we are now experiencing."
OML, formerly Lean Meats, is part of the Chinese-owned BX Foods group, owned by Heilongjiang Binxi Cattle Industry Co Ltd (Binxi).
