Another two million pieces of the Singapore Bicentennial $20 commemorative note and folder will be issued to meet strong public interest, the Monetary Authority of Singapore (MAS) said yesterday.

They are expected to be available around October to November.

All two million $20 notes, issued to mark Singapore's bicentennial year, were exchanged at the banks within a week of the launch, said the MAS. The note was launched on June 5 and was first available for exchange at face value at nine major retail banks on Monday.

Each person was allowed to exchange up to 20 pieces per transaction. There was overwhelming demand from the public for the commemorative note, with long queues seen at bank branches islandwide.

On Monday, five banks told The Straits Times that at least 40 per cent of their overall stocks had been depleted because of demand.

Listings for the $20 notes appeared on online marketplaces at marked-up prices, with some offering them for as much as $1,688 for five pieces.

The MAS will inform the public when the new notes are available for exchange.