Chief Prosecutor Christer van der Kwast said that he was also considering an investigation into suspected bribery in connection with the sale of Gripen planes to South Africa.
The decision to start an investigation into the Czech deal means that authorities in three countries are now examining the case. British and Czech police have already started their own investigations into Swedish arms maker Saab and its British partner BAE Systems.
The two companies worked together at the end of the nineties and the early 2000s to sell 24 Gripen planes to the Czech Republic. They signed an agreement in 2001, which failed to be ratified by the Czech parliament.
From 2002 the Gripen was marketed through a joint venture company, Gripen International, which has been wholly owned by Saab since 2005.
The partnership led in 2004 to a 10 year leasing agreement for 14 Gripen planes between the Swedish and Czech states. It is this agreement that will now be investigated by van der Kwast.