He urged the government to trace the number of Wuhan people in Hong Kong as soon as possible.

“I’m surprised to see the government is still not able to tell how many Wuhan citizens there are in Hong Kong,” Ho said.

Dr Arisina Ma Chung-yee, president of the Public Doctors’ Association, agreed the steps taken were inadequate.

“[Lam] took a step. But it was not fast enough and not big enough,” Ma said. “This situation is not the time for you to dance the tango.”

She said the government did not make any changes at major border checkpoints such as Lo Wu, Lok Ma Chau and Huanggang.

“Many people enter Hong Kong through these checkpoints from Shenzhen … where there are already lots of cases. Therefore I think what the government has done is not enough,” Ma said.

The Hospital Authority Employees’ Alliance branded the measures “slightly more constructive” but they may fail to stop a strike planned by medical sector workers.

The new union, which has attracted more than 12,000 applications to join, said it would go ahead with a general meeting on February 1 to discuss a potential strike over the government’s handling of the epidemic and treatment of frontline staff.

The alliance maintained its call to block all non-Hong Kong residents from entering the city via the mainland.

“Our government has finally been pressured into some progress by us all standing together,” it said.

“Yet, there is still a considerable distance from our goal of full-scale preventive measures of infection control.”

The alliance earlier announced it would move a motion for its members to go on strike early next month if its demands for further immigration control were not met.

Under its plan, the strike would begin in units providing non-urgent services and then include other departments if the government resisted their demands.

More than 40 other unions, many of which were formed in light of the ongoing anti-government protests, also voiced support for the alliance’s plans.

Union for New Civil Servants chairman Michael Ngan Mo-Chau said the group would have a general meeting early next month to discuss if it would take industrial action.

Tourism sector lawmaker Yiu Si-wing said he believed mainland arrivals would drop by half once the new measures were in place, as Lam announced mainlanders would not be able to apply for new individual travel visas to Hong Kong.

Of the 28,000 mainland visitors entering the city on Monday, he said, about 17,000 held business or family visit visas that were unaffected by the latest arrangement. The rest were either visitors from 49 designated mainland cities, or Shenzhen residents holding multiple-entry permits that allowed for one visit a week.

“Those visitors will be vastly reduced as the measures kick in, but bear in mind most cross-border travellers are still Hongkongers, accounting for 67 per cent of the total. What are we going to do about those people?” Yiu said.

The Department of Health only issued a statement on Monday night, advising Hong Kong residents, who have been to Hubei province, centre of the outbreak, over the past 14 days to contact health officers at control points when they returned to the city. Officers would conduct an assessment and demand residents wear a mask immediately even if no symptoms showed. These individuals would also be advised to isolate themselves for 14 days.

The authority also suggested that anyone in the city who had been to Hubei over the past 14 days should contact the Centre for Health Protection hotline at 2125 1122 for advice.

Meanwhile, passengers at Hong Kong International Airport did not object to the cutting of flights and closure of ports.

Ronny Lee, a 50-year-old Hongkonger returning from Britain, said he was relieved that the government announced a partial border closure, but that it was not enough.

“The measures taken by Hong Kong [to combat the virus] are at a lower standard than many mainland cities, even though Hong Kong is a so-called international city,” Lee said.

A Romanian tourist in transit, 41-year-old Cristian Alexander, said a friend had reported flu symptoms on her health declaration form but was allowed entry.

“We were quite surprised,” he said. “I don’t know if the measures are enough to improve the situation.”

At Lo Wu, the busiest border crossing, hundreds gathered around tables to fill out the required health declaration form required by mainland authorities before they left for Hong Kong.

Queues formed as police staff on the Shenzhen side of the border collected and read through the forms before letting passengers through.

Closing the border would be inconvenient, but not upsetting, said Zhan Tianyu, a Shenzhen resident who was on his way to Hong Kong for sightseeing.

“I won’t be too personally affected,” said Zhan, adding that he visited Hong Kong about once a month.

Additional reporting by Victor Ting