Iraqi banks are due to begin issuing new bank notes Wednesday to replace millions of old bills showing the face of Saddam Hussein.

Authorities in the U.S.-led coalition say the new notes have advanced security features to guard against counterfeiting.

The new Iraqi dinars will replace currency that was introduced in 1991 and widely counterfeited. Fears of counterfeiting also spread following the fall of Baghdad, when looters stole Iraqi printing presses.

The new bills were printed in Britain and are an updated version of the so-called Swiss Dinar, used in Iraq before 1991. The bills come in six denominations ranging from 50 to 25,000 dinars.

There are about 2,000 dinars to the U.S. dollar.

Iraqis will have three months to exchange their old cash.