Jan 11 (Reuters) - Ferrexpo reported a 33% slump in annual production of iron ore pellets on Thursday as the Ukraine-focused miner waded through a second year of disruptions caused by the Russian invasion.

The company, which has all its mines in Ukraine, reported total iron ore pellet production of 4.1 million tons for the year ended Dec. 31, compared with 6.1 million tons in the previous year.

London-listed shares of Ferrexpo were down 3.1% in early trade on Thursday.

Ferrexpo had lost access to the Black sea ports, which shipped half of its output before the war, restraining its access to sea-borne markets and forcing it to focus on sales to European customers.

Last year, Ukraine launched a "humanitarian corridor" for ships bound for African and Asian markets and opened certain ports.

Swiss-based Ferrexpo plans to resume trade via this route and start an additional pellet line.

"Even with winter setting in, we have been able to operate one, sometimes two, of our four pellet lines, to match the reduced export capacity available to us," Interim Executive Chair Lucio Genovese said in a statement.

(Reporting by Anchal Rana in Bengaluru; Editing by Subhranshu Sahu and Sherry Jacob-Phillips)