The State Bank of Vietnam said it has allowed several banks to reopen gold trading accounts in the international markets after a 15-month ban to bring down the gap between domestic and world prices.

The banks can also sell physical gold from their stock and deposits to raise the supply in the domestic market and narrow the premium, the central bank said in a statement late on Thursday, without giving the names of the lenders.

The central bank has however, added some tough measures to ensure that the restart of gold trading accounts is not used for speculating on bullion prices, but is used to manage risks of fluctuating prices.

It did not elaborate on the measures in the statement.

Vietnamese banks were ordered to close offshore trading accounts by the end of June 2010 to restrict gold transactions and help stabilise the dong .

Six institutions, including the partly private DongA Bank, Asia Commercial Bank , Techcombank, Eximbank , Sacombank and the country's top gold trading company Saigon Jewelry Co (SJC), can now buy and sell gold at the same price quoted by SJC, the news website VnExpress (vnexpress.net) said.

They sold a total of five tonnes of the metal on Thursday, bringing the premium down to 1 million ($49.2) a tael from around 3 million in the earlier days, state-run newspaper Tuoi Tre said on Friday.

One tael is equivalent to 37.5 grams or 1.21 troy ounce.

SJC was selling a tael at 43.97 million dong at 0330 GMT on Friday, around 0.4 percent lower than a day earlier.

Gold prices in Vietnam ran counter to the international market where the yellow metal headed for its biggest weekly gain in a month, adding $7.44 to $1,656.79 an ounce by 0313 GMT.