At least six of Zimbabwe's newer commercial banks are in trouble, and many retailers are refusing to accept their checks or guarantees. The growing turmoil in the banking sector follows the government's new monetary policy announced in December, in which the central bank vowed to stop speculation in the Zimbabwe dollar and related investments.

Most mainstream retailers have a list at their check-out counters with the names of banks from which they will not accept checks.

In addition, some of the larger and older banks are not clearing checks from some smaller banks, several of which were established by prominent members of the ruling Zanu PF party.

The new governor of the Reserve Bank, Gideon Gono, has said he will not lend money to banks which, in turn, lend to clients who engage in currency speculation. Some of those clients buy foreign currency a high rates, hoping the rate will go even higher. Others buy luxury goods, such as cars or jewelry, hoping their value in Zimbabwe dollars will go up dramatically.

Mr. Gono said banks must only lend to those who will use the money to enhance Zimbabwe's productivity.

The acting-chief executive of the Confederation of Zimbabwe Industries, Farai Zizhou, said Monday that Mr. Gono is trying to clean up the country's international image. Mr. Zizhou also noted that the central bank wants to gain control of foreign currency transactions in order to have the funds to repay its debt to the International Monetary Fund. Zimbabwe has not been able to make even minimum required repayments.

Next week, the Reserve Bank is due to begin foreign currency auctions in what it says is a move to end black market trading.

Several banks have been ordered by the Reserve Bank to make sure they can meet commitments to depositors. This has resulted in some banks disposing of hoarded foreign currency, luxury vehicles, houses and jewelry.

The short-term result is that the black market for U.S. dollars has dropped to about $4,500 (Zimbabwe) to $1 (US), from about $6,000 (Zimbabe) a week ago.

Several leading exporters say this has affected their ability to do business, because they have only managed to stay afloat by cashing foreign currency at the top rate.

Economist John Robertson said Tuesday the long expected meltdown of Zimbabwe's financial sector has begun. The opposition Movement for Democratic Change said Tuesday the financial crisis was caused by rampant corruption.

Zimbabwe has 17 commercial banks, and more than a third now have liquidity problems, including the government's Agri Bank, which has lent an undisclosed amount to new farmers. These farmers were given land confiscated from white commercial farmers, and have not managed to grow adequate crops to repay their loans.