In its first week of circulation, about 35 million $10 polymer notes were issued, Hong Kong Monetary Authority Chief Executive Joseph Yam says, adding the public's initial response has been mostly favourable.

Writing in his weekly Viewpoint column, Mr Yam outlines the history of the $10 note in Hong Kong.The latest version allows for the introduction of security features that are not available with paper notes, such as the clear window and colour-shift ribbon, he notes. These also make the new notes quite easy to identify.

"People seem to agree that the new notes are clean and durable, do not get dirty easily and have a 'crisp' feel. Because polymer notes are sturdier and last longer than paper notes, and can be recycled when they are no longer useable, they should also be kinder to the environment and, equally important, more cost-effective," he writes.

"People have already asked whether the introduction of this note means that we are planning to extend the use of polymer to the other denominations. The answer is that we have not yet decided. This is a trial issue and we want to evaluate, over the next two years, the public reaction to the new notes and whether they really deliver the benefits - in terms of durability, security and cost effectiveness - that we are expecting."

He encourages members of the public to send their comments on the new notes to polymer_note@hkma.gov.hk.