SYDNEY -- Anglo-Australian miner Rio Tinto has downgraded the shipment forecast of Australian iron ore due to labor shortages and delayed development of coal mines in Western Australia, the company announced on Friday.

The company revised the shipment forecast to 320 million to 325 million tons in 2021, down from the previous forecast of 325 million to 340 million tons. The last time the company's Australian iron ore shipment was under 330 million tons was in 2019, when it was affected by cyclones and other weather conditions.

"Despite improving versus the prior quarter, we recognize the opportunity to raise our performance," Rio Tinto's chief executive Jakob Stausholm said in a quarterly report.

There has been a labor shortage in the state of Western Australia due to movement restrictions under the coronavirus pandemic.

"Restrictions on movement and availability of people can impact our ability to execute planned maintenance and deliver or accelerate projects," the company's report said.

Rio Tinto's iron ore shipments totaled 83.4 million tons in the July-September quarter, up 2% from the same period last year. Production fell by 4% to 83.3 million tons. This was due to "[Aboriginal] heritage management, brownfield mine replacement tie-ins and project completion delays," according to the company.