Vetter, whose appointment helps fill a leadership vacuum at Germany's second largest lender, is expected to lead the search for a new chief executive at Commerzbank, whose shares have slumped around 60% since Cerberus bought its stake in 2017.
Commerzbank was thrown into turmoil last month when CEO Martin Zielke and supervisory board chairman Stefan Schmittmann stepped down to give the 150-year-old lender a fresh start.
However, Monday's move to appoint Vetter risks further antagonising activist U.S. private equity investor Cerberus, which holds a 5% stake and has led a vocal campaign for change.
Cerberus, the second-largest investor in Commerzbank after the German government, sent a letter to the bank's supervisory board ahead of Monday's meeting about the vacant chair position.
It said Cerberus had concerns about Vetter and that the investor had its own names to pitch, adding that the person selected as chair must help initiate and support a "necessary, far-reaching restructuring" at Commerzbank.
"We have serious doubts that Hans-Joerg Vetter is the right person for this job or has the right experience for it," Cerberus said in the letter, a copy of which was seen by Reuters. A spokeswoman for Commerzbank declined to comment.
"Cerberus has identified at least two candidates who have the required qualifications to fill the role of chairman and secure the confidence of all key stakeholders," Cerberus said, without naming them.
Vetter is a former chief executive of Landesbank Baden-Wuerttemberg whose supporters say he has restructuring and retail banking experience from his time there and previously as CEO of Bankgesellschaft Berlin.
Commerzbank has in recent months swung to a loss, halted its 2019 dividend plans, backtracked on selling Polish lender mBank and had its credit rating downgraded.
By Tom Sims and Hans Seidenstuecker