German heavy industry giant ThyssenKrupp on Thursday defended its disputed merger with India's Tata Steel, saying its restructuring plan and the tie-up would help to secure tens of thousands of jobs.

The tie-up, announced end-September to form Europe's second biggest steel works after ArcelorMittal, has sparked fears for 4,000 jobs in production and administration that hang in the balance.

On Thursday, thousands of workers, some holding up signs saying "We are the future", answered a call by metal works union IG Metall to protest at the group's Andernach site in western Germany.

But ThyssenKrupp chief executive Heinrich Hiesinger defended the merger and planned overhaul at the conglomerate, saying: "We will perhaps cut thousands of jobs, but we will also secure tens of thousands of jobs with this co-enterprise."