* Metinvest accounts for around 40 pct of Ukraine's steel output
* Company to focus on fulfilling existing contracts (Adds detail, background)
MOSCOW Aug 1 (Reuters) - Metinvest, Ukraine's largest steelmaker, said on Friday it was no longer accepting new orders from buyers due to the months-long crisis in east Ukraine which has forced it to cut production.
Ukraine was the world's fifth-biggest steel exporter last year but many of the operations of the country's producers have been disrupted this year by months of deadly fighting between pro-Russian separatist rebels and government forces in the country's east.
"Until the situation becomes clear, the decision was taken to stop taking new orders and focus on fulfilling existing contracts," a Metinvest spokesman said.
The company added that it had a strong order book for August and September.
Metinvest, which is privately held and controlled by Ukraine's richest man, Rinat Akhmetov, has had to limit output at two steel mills due to supply issues arising from the conflict, while production was temporarily halted at its main coke plant after it was hit by artillery fire.
The company produced 12.4 million tonnes of crude steel in 2013 or nearly 40 percent of Ukraine's total output. (Reporting by Andrey Kuzmin; Writing by Alessandra Prentice; editing by Thomas Grove and Greg Mahlich)