H ANOI - Vietnam has started curbing the use of the US dollar, which has served for years as a parallel currency to the dong.

First indications were that the new foreign exchange rules, requiring the dong to be used for nearly all transactions, had little impact.

Most hotels were still billing customers in dollars, though some smaller ones charged guests in dong, changing their dollars in front-desk exchange kiosks.

Some shops which previously charged in dollars became "exchange agents" for the banks, continuing to take dollars and changing them on the spot into dong. They would then deposit the dollars in the bank.

"It's like a house with two doors," said a hotel employee. "You go in one door with dollars and you change them into dong. For the guest, it doesn't make any difference."

Prime Minister Vo Van Kiet ordered the changes last August to suck at least $600 million in dollar notes circulating in this communist country of 72 million people into the banking system.

Hotels, restaurants, landlords, some shops and Vietnamese state and private companies - now required to deposit their hard currency earnings in bank accounts - were among the businesses most likely to be affected.