Liberty said the cost of production was unaffordable given low finished steel prices.
Liberty won the tender for the struggling plant in mid-July, buying it out of liquidation for €55 million. It was competing with Vulcan Steel, an organisation close to Naveen Jindal, in the final stage of the bidding process. Ukraine's Metinvest, which was eliminated from bidding in an earlier round, said the value of the plant was close to €200 million.
The sale of Dunaferr was conditional on the company's continued economic activity. The plant's rolling lines are currently operational.
A spokesperson for Liberty Steel declined to comment on the suspension of production or how long it would last.