"The preparation to separate the TUI Group's shipping division is progressing according to plan," Frenzel said in a speech to be delivered at the company's annual meeting later on Wednesday.
"We do not rule out any of the potential options, although our clear preference is a divestment solution," he said, adding that a preliminary decision had not been taken regarding potential buyers.
He said a merger would be too time consuming and a spin-off would be a long-winded option requiring "the group to be completely refinanced, a condition hardly perceived as possible at appropriate terms and conditions under current market conditions."
TUI owns a 51 percent stake in TUI Travel , Europe's biggest tourism firm, and owns Hapag-Lloyd, the world's fifth-largest container shipping firm that some analysts say could fetch around 4.6 billion euros ($7.12 billion) if sold.
He said the nationality of the buyer would not matter.
Some shareholders have said in recent weeks that Frenzel would orchestrate a deal to please politicans rather than shareholders.
"What matters is not the nationality of the buyer but the question as to whether the buyer has the necessary know-how and the financial resources to ensure a successful further development of Hapag-Lloyd," Frenzel added. "This is the only way to secure jobs and sites in the long run."