White House Chief of Staff John Sununu is seeking to block a second five-year term for Comptroller of the Currency Robert L. Clarke, after complaining in recent White House meetings that Clarke's oversight of national banks is so tough that it has caused a nationwide credit crunch, Bush administration officials said yesterday.

Apparently at the behest of Sununu, calls have been made this week to bankers and other business executives soliciting opinions about Clarke. While there is no firm timetable, one administration official said he expects the president to make a decision on the nomination early next week.

"Sununu is among those who oppose Clarke's nomination," an administration official confirmed.

Clarke's reappointment is supported by Treasury Secretary Nicholas F. Brady. The Office of the Comptroller of the Currency (OCC) is part of the Treasury and regulates federally chartered banks, which include most of the nation's largest.

Some administration officials said Clarke was assured by the White House as recently as last Thursday of his reappointment, but another official flatly denied that any assurances were given.

In any event, word began to circulate yesterday among federal banking regulators that the calls were being made and that Sununu opposed the nomination.

At a White House meeting Nov. 14 at which President Bush was briefed by Clarke and officials from the Federal Reserve System and the Federal Deposit Insurance Corp. on the status of the banking system and credit conditions, Sununu complained that regulators had forced banks to tighten their lending standards too much. He and Commerce Secretary Robert Mosbacher said the result was a slowing of loans to businesses that is making the current economic downturn even worse.

The issue also came up the next day when Bush met with a group of bankers and business executives to discuss the state of the slumping U.S. economy and the banking system.

Clarke's examiners have drawn the fire of some bankers and business officials because they have forced banks to adjust their books to reflect the likelihood that some loans they have made are unlikely to be repaid. Such steps force the banks to set aside money to cover possible losses, leaving the banks less able and less willing to make new loans.

According to industry officials and bank regulators, the OCC under Clarke has been returning to stiffer examining standards after becoming more lax during the 1980s. The other federal regulators -- the Fed and the FDIC -- did not relax the standards by which they judge bank performance and thus have had to make fewer adjustments in the past two years.

Despite the complaints, Clarke has refused to back down, saying that OCC examiners are generally doing only what they must to ensure that banks remain safe and sound during a period of weak real estate markets and rising loan losses.

"It is obvious that they don't like the fact that Mr. Clarke has designated himself as the regulator from hell," another official quipped.

Some administration officials said the purpose of the calls now being made to bankers and business executives around the country is to build a case against Clarke, whose first term expired on Dec. 1. Another administration official, however, said the calls' purpose was more neutral, to solicit opinions from around the country about Clarke's performance.

The president has received at least one letter signed by a number of large contributors to the Republican Party urging that Clarke be dumped, but that did not deter Brady from urging Bush to reappoint him, the official said.

"Brady is on his side," the official said. "The protest came in very late in the game. Sununu had previously been protesting, relying on his friends in New Hampshire."

Prior to coming to Washington, the chief of staff was governor of New Hampshire, which like the rest of New England is in the midst of a serious economic slump. Many New Hampshire banks have suffered large loan losses, and at least one bank in the state has failed this year.

Most New England banks have cut back their lending this year, both because they have tightened lending standards and because with the economic outlook so poor, loan demand has dropped.

Bankers in the region are willing to make what they regard as "good" loans. But even the new loans they are willing to make routinely are for smaller amounts than they would have made as recently as a year ago, with the borrowers being required to put up more collateral and to offer personal guarantees that the loan will be repaid.