AUTHORITIES are working with operators and suppliers to ensure the new $10 coin will be accepted by vending machines, the Acting Secretary for Financial Services, Tam Wing-pong, said yesterday. The new $10 coin is lighter than the existing $5 coin - the former weighs 11 grams and the latter 13.5 grams. The possible inconvenience caused to the public was minimal, Mr Tam said. The circulation of the $20 notes will be increased so the public could choose to carry bank notes in a higher denomination instead of coins if they wished so.