Three former employees of Finnish defence company Patria Vehicles, including the ex-chief executive, have been charged with bribery over a multi-million-euro arms deal with Croatia, Finland's prosecution service said.

The three are suspected of the "promising or giving of bribes through intermediaries in exchange for actions of the president of the Republic of Croatia and the general manager of a Croatian state-owned company," the prosecution service wrote in a statement issued late Friday.

The case involved the sale of armoured modular vehicles (AMVs) to Croatia in 2007.

The suspects are alleged to have "promised and partly paid out bribes amounting to five percent of the selling price of the AMV vehicles," the prosecution said.

In 2005, Patria Vehicles, a subsidiary of the state-owned Patria Group, offered AMVs to Croatia for more than 350 million euros ($455 million).

Two years later, an agreement for the purchase of a limited number of vehicles was concluded, with Patria's share of the deal more than 50 million euros, the prosecution said.

"Patria Vehicles paid out 1.5 million euros, part of the alleged bribes, to an intermediary in Austria," it said.

"Further money transfers in Austria raised suspicion of money laundering and corruption."

Former Croatian president Stipe Mesic has rejected the allegations.

Investigations are also underway in Austria and Croatia.

The same defendants have already been charged with bribery in a case concerning armoured vehicles Patria sold to Slovenia.

The suspects have denied the accusations.

In the Slovenia case, the investigation focused on a 278-million-euro deal in 2006 that led to formal bribery charges against former prime minister Janez Jansa in September 2010.

Jansa has consistently denied the allegations.