By Arno Schuetze

FRANKFURT (Reuters) - Pressure mounted on TUI AG (TUIGn.DE: Quote, Profile, Research) on Tuesday to axe its supervisory board chief after Norwegian shipping tycoon John Fredriksen said he would not take a seat on the board if Juergen Krumnow did not quit.

"We don't want to work with a supervisory board that would continue the cronyism of (TUI Chief Executive Michael) Frenzel and Krumnow," said a spokesman for Fredriksen, who is TUI's biggest shareholder with an 11.7 percent stake.

TUI's biggest shareholders are at loggerheads with each other and management before Wednesday's annual meeting at Europe's biggest tourism group, whose Hapag-Lloyd unit is the world's fifth-largest container shipping company.

Another TUI shareholder, activist U.S. investor Guy Wyser-Pratte, who holds a 1 percent stake in TUI, told Reuters Frenzel and Krumnow should step down.

In an e-mailed response to questions, Wyser-Pratte said Frenzel had "accomplished nothing in 14 years except destruction of shareholder value of 25 percent, vis a vis a 256 percent increase in the (German blue-chip index) DAX."

"Everything he sold has tripled in value and everything he bought, he bought at the top. For all this 'superb performance', his salary has quadrupled. It is time for him to go."

Wyser-Pratte added that he did not "trust Frenzel to act in the interest of the shareholders. He and Krumnow never have. I expect them to attempt a 'politically soothing' solution at under fair market value" for the sale of Hapag-Lloyd.

TUI declined to comment on the shareholder criticism.