The United States Treasury will release a new $20 bill this week as a result of an increase in counterfeit US money.

And US Consul Denis Coleman said the US will continue to change the design of its currency every seven to ten years, with newly designed $50 and $100 anticipated for release in 2005.

The new $20 bill, which will be released on October 9, will feature background colours and updated security features designed to make it harder to counterfeit and easier to authenticate.

Diverting from the traditional US greenback, the new notes have subtle green, peach and blue features in the background.

The notes retain three security features first introduced in the late 1990s: the watermark (a faint image similar to the large portrait, part of the paper itself and visible from both sides when held up to the light), the security thread (also visible from both sides, embedded in the paper and reading "USA TWENTY" with a small flag), and the colour shifting ink in the numeral 20 in the lower right corner on the face of the notes.

This ink changes from copper to green when the notes are tilted, and is more dramatic on the new-design notes.

The redesign also features symbols of American freedom: a blue eagle in the background to the left of the portrait, and a metallic green eagle and shield to the right of the portrait.

As is the case with all US currency, the new notes will be interchangeable with US currency already in circulation.

All denominations of notes, new or old, will continue to maintain their current value.

The US Government initially unveiled the new $20 design last May to allow the public time to prepare, and has been working with the vending machine industry for over a year to ensure their equipment is compatible.

The redesign of the $10 and $5 notes is under consideration, however there are no plans to redesign the $1 and $2 notes.

Last year the US Secret Service and international authorities seized $130 million in counterfeit US notes before they made it into circulation.

The total amount of counterfeit US money in circulation world-wide is estimate at $70 million to $170 million at any given time.

An interactive demonstration on the new bill's security features is available at www.moneyfactory.com/newmoney.