Amsterdam - Fortis shareholders are testing the waters to see if they can file a lawsuit against the Dutch bank after it was nationalized last month.

Details of the claim, which is being prepared by De Gier Business Law, are sketchy. It is not clear if shareholders would seek damages against Fortis NV for losses incurred after its nationalization or if a suit would merely seek to assign blame for the steps that led to the nationalization.

In the past two weeks, local subsidiaries of the former Dutch- Belgian insurer and bank giant were taken over by the Dutch, Belgium and Luxembourg governments as well as French BNP Paribas bank.

The measure was necessary to prevent the bank from collapsing. Fortis suffered from liquidity problems after the takeover of Dutch ABN Amro bank in October 2007.

Last week, De Gier said several shareholders had requested the firm to investigate whether mistakes were made during the recent takeovers by local governments and BNP Paribas bank, possibly harming the interests of the shareholders of parent holding Fortis NV.

De Gier says the shareholders are holding not only Fortis management responsible for possible damage, but also the Dutch central bank DNB, the watchdog of the financial markets AFM, as well as the governments of Belgium and the Netherlands.

In addition, the shareholders claim present and former Fortis top managers, such as Maurice Lippens, Jean-Paul Votron, Herman Verwilst and Filip Dierckx are to be held personally accountable for mismanagement and for failing to provide transparency.

De Gier says it is discussing the preparation of an international claim against Fortis with international law firms, adding that more details will be released by the end of this week.

Meanwhile the Dutch shareholders association VEB said it has demanded an extraordinary shareholders meeting from Fortis. Fortis has not responded yet.

Trading in Fortis shares resumed at 11 am (0900 GMT) on Tuesday. By 3:30 pm (1330 GMT), Fortis shares had dropped 68.76 per cent and stood at 1.69 euros, 5 per cent of its value on January 2. (dpa)