By Tom Käckenhoff and Christoph Steitz
DUESSELDORF/FRANKFURT (Reuters) -Thyssenkrupp's labour bosses cranked up the pressure on Berlin to help fund a 2 billion euro ($2.2 billion) green steel production site, warning in a letter to Economy Minister Robert Habeck that a further subsidy cut could choke off the project.
Reducing support further would trigger a "massive discussion" within Thyssenkrupp's supervisory board over whether to pull the plug on the investment, the letter, dated May 17 and co-signed by the group's deputy chairman Juergen Kerner, said.
The letter did not disclose either how much Berlin had proposed in state help, or by how much this had been reduced.
The conflict lays bare how much industrial heavyweights depend on aid to decarbonise their businesses as well as the need for governments to approve subsidies quickly to avoid companies from shifting investments or stopping them altogether.
Thyssenkrupp in August made the investment decision for the so-called direct reduction iron (DRI) site at its steel base in Duisburg, provided substantial subsidy commitments by the state of North Rhine-Westphalia and Berlin were fulfilled.
"There is still no funding commitment and in talks between Thyssenkrupp and (the Economy Ministry) it is becoming apparent that there is massive resistance in Brussels and/or Berlin to approve the promised subsidies," the letter said.
Thyssenkrupp had no immediate comment.
The Economy Ministry repeated previous comments, saying it continued to support Thyssenkrupp's plans but could not approve the funds without consent from the European Commission, which is still outstanding.
Tekin Nasikkol, who heads the works council of Thyssenkrupp Steel Europe, told Reuters last week that Berlin needed to quickly approve hundreds of millions in subsidies for the site, adding workers' patience had run out.
The letter, which was also signed by Nasikkol, said a decision over whether to revoke the investment was delayed to June 23, inviting Habeck to a worker gathering in Duisburg in the middle of next month.
($1 = 0.9084 euros)
(Reporting by Tom Kaeckenhoff and Christoph Steitz; Additional reporting by Christian Kraemer; Editing by Friederike Heine and Mark Potter)