Five cross-border drivers have tested positive for Covid-19 since last Friday, according to Shenzhen authorities, as fresh food suppliers heading into Hong Kong were allowed to gradually resume operations at a major checkpoint on Monday evening.

Unionists said they believed it may take more time for supplies, which had been affected by Covid-19 disruptions, to fully recover if the outbreak continues.

The Hong Kong government said on Tuesday afternoon that vehicles at Man Kam To Control Point were allowed to resume operations at 9pm on Monday. It added that some drivers were previously stuck at the checkpoint as they waited for authorities to disinfect a site for handing over goods.

Vegetable supplies decreased to about one-third in light of the incident, according to the government. But by morning, traffic had returned to normal and the government said it expected supply would rebound quickly.

Man Kam To control point is a major gateway for fresh foods – including vegetables, meat and fish – going from mainland China to Hong Kong. The city receives 92 per cent of its vegetables from the mainland.

About 22 trucks at the control point managed to leave Hong Kong on Monday evening, according to Chan Dik-sau, chairman of the Container Transportation Employees General Union.

Three of the five cross-border truck drivers who were infected with Covid-19 tested positive for the virus after returning to Hong Kong. The other two drivers tested positive at Shenzhen Bay Port. A number of drivers were also reportedly sent to quarantine.

President of the Hong Kong Imported Vegetable Wholesale Merchants Yuen Cheong said he was waiting for updates on whether more drivers had been infected. He added that operations could gradually return to normal if there were no new cases.

But Chan said he was worried more drivers would test positive.

“That’s why we hope the Hong Kong government can control the outbreak here. Otherwise, more drivers [are at risk of] testing positive, which will affect [food supply] measures,” Chan said.

People buying vegetables and fruits at a wet market in North Point.

Cross-border drivers were also required to stay at designated hotels on the mainland before taking on their next job, he said.

Vegetable prices in the city could remain high over the coming days, as cross-border truck drivers face tighter testing requirements since Tuesday, requiring them to provide a negative test result within 24 hours of reaching control points, instead of the previous 48-hour rule.

Some vegetables, including Chinese green cabbage and watercress, have seen drastic price increases. Some residents have had to absorb the higher costs or resort to buying cheaper alternatives, while vendors have complained about decreasing stocks and profits.