It stopped output at Port Pirie on May 28 due to an unplanned outage at the blast furnace, a spokesman said in a email.
"We are currently in the process of assessing the outage and expect that production should resume within the coming days. There will be a negative impact to Nyrstar’s lead metal production due to the outage," he added.
Port Pirie produced 160,000 tonnes of lead metal last year, down 7 percent from the previous year.
(Reporting by Eric Onstad. Editing by Jane Merriman)