Some said they had benefited from relatives and friends living abroad when they failed to get a mask during an earlier buying craze in the city, but now it was their loved ones who struggled.

In February, Hongkong Post increased staffing levels and extended delivery hours to cope with an 80 per cent surge in the daily volume of inbound parcels.

Around 30,000 express items containing masks were delivered in the first nine days after postal service resumed on February 3, following a temporary suspension.

A spokeswoman for the postal service said while the volume of incoming mail had stabilised, demand for the outbound express service had doubled since last week, with up to 40 per cent of parcels believed to be anti-contagion items.

The change in tide followed the worldwide outbreak of the deadly coronavirus, which was first reported in mainland China.

More than 400,000 Covid-19 infections have been recorded around the world, and over 18,000 people have died.

Recently, the mask shortage in the city has eased, with at least 13 organisations and firms setting up local production lines. Among them, seven have started or plan to begin operations in April, and three have already opened for pre-orders.

On Tuesday, saleswoman Mandy Tam, 50, lined up outside a post office in Yuen Long to return more than 200 of the 400 masks her elder sister had sent to her from London.

She said many people in Britain remained nonchalant about the virus and had yet to pick up the habit of wearing a mask when they went out.

Also in the queue was Kary Mak, who wanted to send 150 masks to her cousin in New York. The 40-year-old jewellery shop worker was repaying the favour, after her relative in the US sent her a box of 30 masks last month.

Estate agent Mike Lam said the surge in confirmed cases outside China was the result of a general lack of sensitivity to the global health issue.

“People didn’t expect an outbreak in their community, thinking that it was a China problem,” Lam said.

The 38-year-old had spent around HK$5,000 on 800 masks, which he sent to his friends in the Netherlands and Belgium over the past week after they failed to buy masks.

Lam said people living there were not alert enough and said if they did not have masks, “they may just cover their face with a scarf”.

Retiree Mr To, in his 60s, was sending masks to his cousin in Rotterdam. He said his cousin had witnessed locals insulting and attacking Asians for wearing a mask.

“People know they have to wear a mask, but the problem is that you’ll get into trouble if those Europeans spot you wearing one,” he said.

At a courier office in Admiralty, local resident Leonor Herbet sent 600 masks to her friends in New York, London and Barcelona. She said people overseas had reacted late and were now struggling to get protective gear.

Herbet said she had previously been turned down by friends overseas when she said she could send masks to them.

“They said ‘no problem, this is London’. Now they’re panicking,” she said.