FRANKFURT, Sept 17 — The European Central Bank today unveiled new versions of the €100 and €200 banknotes, saying new security features would make them harder to counterfeit.

Like other second-generation notes in the "Europa” series introduced since 2013, the new paper money includes different holograms in a silver strip and an "emerald number” showing the denomination -- this time in an enhanced form with small euro symbols inside the numerals.

Designers also reduced the notes’ height to match the €50 version.

That leaves the length of the paper as the only size difference between denominations, with longer notes bearing a higher value.

The green €100 banknotes represent some 23 per cent of the value of euro paper money in circulation, ECB board member Yves Mersch told reporters in Frankfurt, making them "not just a niche product and also not just a rich (person’s) product.”

Before the new notes are introduced on May 28 next year, more than one million ATM machines must be updated to take account of the changes.

While national central banks in the 19-nation eurozone are responsible for their own coins, the ECB designs and issues all the banknotes for the single currency area.

With their artwork depicting different architectural styles from European history, some critics have labelled the euro banknotes bland. — AFP