Surgical masks are washing up in growing quantities on the shores of Hong Kong, a city that has overwhelmingly embraced face coverings to fight the coronavirus.

Conservationists say the masks are adding to already alarmingly high levels of plastic waste in the waters around the finance hub.

"The single use plastic mask is just another additional burden that we are leaving behind for the future generations," Gary Stokes, co-founder of OceansAsia, told AFP.