Shares in technical service provider Imtech plunged on the Amsterdam stock exchange on Monday after the company said it was forced to write off €100m on its Polish activities because of possible fraud.

Imtech has also delayed publishing its 2012 annual report, which was set for Tuesday, the Gouda-based company said in a statement.

In the statement, Imtech said it had been ‘severely harmed’ by the ‘lack of financing of its largest customer in Poland’. The company has ordered a forensic investigation and suspended its local Polish management.

The problems concern three projects for Adventure World Warsaw and one project involving energy-generating biopower stations, also in Warsaw. These projects have a combined value of €757m, Imtech said.

The Polish adventure park was Imtech’s largest ever order, the Financieele Dagblad reported.