Vietnam is considering outlawing the use of US currency in a bid to shore up its troubled dong as the regional crisis worsens. Government officials confirmed reports that central bankers were seeking approval to tighten existing regulations to effectively ban its widespread day-to-day use. 'It is under active consideration but no regulations have been finalised yet,' one source said. 'Vietnam has tolerated effectively a dual currency for some time. 'Few countries would have done that and maybe now it is time for that to end.' The semi-official Vietnam Investment Review quoted acting deputy State Bank governor Do Que Luong as saying the non-covertible dong would soon become the country's only legal currency. Foreign investors said they hoped clear decisions would be made soon as any uncertainty over the ability to obtain and hold US dollars only worsened an already bleak investment picture. The slow but steady stabilisation of the dong in recent years has been considered an economic success story. Since slowly opening its doors 10 years ago, Vietnam has placed a priority on stabilising and spreading support for the dong after years of hyper-inflation sparked the creation of a vast underground economy based around gold and US dollars. The collapse of rival regional currencies such as the Thai baht has put the currency under vast new pressures in the race for exports. Fears of massive devaluations remain constant on the streets and have led to the return of the first black market in years. Despite de-facto devaluations of about 10 per cent through the movement of its inter-bank trading band, the government wants to avoid further slides to ensure public support. Economists said outlawing the use of foreign currencies could be an effective way of supporting the currency in the short-term. 'In reality, it could be very difficult to enforce,' one Hanoi-based foreign economist said. 'So many government agencies and state landlords like to deal in dollars with foreigners. 'The whole economy is steeped in the greenback and has been so for years. 'It's a gamble for the government. The price of failure could be very high in damaging the reputation of the currency.' Tighter regulations were introduced to hotels, restaurants and shops in 1995 but made little clear headway.