The alarm was sounded at a workshop sponsored by the State Bank of Viet Nam (SBV).
It revealed that essential guidelines for the implementation of new laws governing competition and credit institutions have still to be issued, leaving loopholes in the system.
Deputy Director of the SBV Banking Department, Truong Ngoc Anh, said the three categories of banks in Viet Nam - State-owned, joint-stock and branches of foreign banks - targeted different customers.
As a result, competition existed only between banks within the same category.
But once foreign banks entered Viet Nam, the market would witness growing competition between them and this would require preparation of a firm legal basis to restrict unfair practices.
A survey of the banking industry by lawyers at Bao and Associates law firm shows unfair competition dominant in the attraction of deposits, marketing and services.
The firm chief executive director Thai Bao Anh said the unfair competition was identified in manipulative advertising or the offering of less-than-cost service fees.
However, he conceded that so-called unfair competition was the subjective view of individuals who took part in the survey and that official complaints were never lodged with the Trade Ministry Department of Competition Administration.
The workshop participants agreed that a lack of ground rules made it very difficult to prove if action by one bank harmed its rivals.
A bank that introduced a deposit programme offering very high interest could easily be accused of unfair business practise if its rivals argued that the rate was uneconomical and aimed only at market expansion.
But proving the accusation would be difficult because factors such as its capital balance and efficiency would have to be taken into account.
A marketing ploy such as telling would-be customers that "Depositing your money with our bank is very safe because a State-owned bank never fails" might also be considered unfair.
The workshop concluded that all of these possibilities - as well as others - need to be quickly and clearly included in the proposed guidelines to the competition laws so as to ensure a healthy banking industry.
Vietnam News, July 6