Traian Basescu was transport minister in the early 1990s

The charges are connected with the sale of 16 ships by the state-owned Petromin company to a Norwegian enterprise in the 1990s, prosecutors said.

The officials are accused of defrauding the state of around $300m (�164m) in revenues in exchange for bribes.

Mr Basescu has denied the charges, saying they are politically motivated.

He said that they had been prompted by a strong showing in opinion polls for his opposition Democratic Party ahead of general elections due in November.

"This charge is the result of a political order that seeks to discredit an opponent before the legislative elections," he told reporters.

The mayor, who was minister of transport at the time the offences are alleged to have taken place, added that it was regrettable that "80 people who did their duty honestly have been brought before the courts".

The Norwegian company, Torvald Klaveness, also denies any wrong-doing.

The European Union, which Romania hopes to join in 2007, has urged the government to do more to fight corruption.