WASHINGTON, April 25 -- Escalating his campaign to remain president of the World Bank, Paul D. Wolfowitz accused the bank's board on Wednesday of treating him "shabbily and unfairly," and appealed for more time to defend himself against allegations of favoritism and other matters.

Mr. Wolfowitz, increasingly isolated at the bank and facing a board seemingly determined to force his resignation, sent a letter to the head of a board panel dealing with issues affecting his leadership, asking to appear before the board next week in the interest of "fairness to me" and "good governance" at the bank.

The letter was described by people who had seen it.

Bank officials described many on the 24-member board as having been taken aback by the tough tone of the letter but said the board appeared likely to grant Mr. Wolfowitz at least some of his request, perhaps by allowing him to appear next week, though not necessarily with his newly hired lawyer, Robert S. Bennett.

Before Wednesday, the board had seemed to be moving toward some sort of vote as early as this week on Mr. Wolfowitz's ability to continue as president. The board met late Wednesday, but officials said it appeared unlikely to reach any quick conclusions and could put off the response to Mr. Wolfowitz until next week.

Compounding the problems for Mr. Wolfowitz, the bank's vice presidents have rebuffed his request for them to set up a committee to advise him on improving his management style. The vice presidents did not want to be co-opted into helping his campaign to stay in office, bank officials said.

Although he appears to be more and more beleaguered, Mr. Wolfowitz attended a White House meeting on Wednesday on malaria eradication, and got a new gesture of support from President Bush.