Hong Kong's rival political camps have embraced a new tactic to woo potential voters as the city hunkers down during the coronavirus pandemic: free face masks.

Masks have been in desperately short supply in Hong Kong since the start of the year when the epidemic reached the financial hub.

Politicians from both the resurgent pro-democracy camp and their embattled pro-Beijing rivals have seized on the shortage, beginning a charm offensive with voters even before official campaigning kicks off for the city's legislature elections in September.

Already riding high after last year's huge anti-government protests, three pro-democracy parties were the first to pull off something of a public relations coup -- securing 1.2 million masks form Honduras.

The move did not go unnoticed, and one week later the pro-Beijing camp announced that had one million masks of their own.

Local councillor Eason Chan said he believed the swift response from the pro-democracy camp to the virus pushed their opponents to up their game.

"That we started earlier and kept bringing supplies to the community, in some ways, forced all parties to join the competition," he told AFP.

"The Pro-Beijing camp wants to use this chance to return to the community and reinforce their local support," he added.

Beijing's powerful Liaison Office in Hong Kong announced the neighbouring Chinese mainland city of Shenzhen had donated one million masks that were being distributed among the community by a newly-formed group called "Hong Kong Community Anti-Coronavirus Link".

"As long as the public can be benefitted, it's fine for different parties in society to do their own part," said Bunny Chan, a well-connected politician within the pro-Beijing side and one of about 30 conveners of the Link.

Our conveners have either extensive local networks or professional background, and we have more than 5,000 volunteers across the city to help," he told AFP.