More effective and concrete measures to prevent and control the spread of novel coronavirus will be introduced in Guangzhou, Guangdong province, a health official promised on Tuesday as the number of confirmed cases and asymptomatic carriers detected in the city continues to grow.

Guangzhou recorded 11 confirmed cases, plus two asymptomatic carriers, on Monday, pushing the number of confirmed cases in the city since May 21 to 34. There have also been eight asymptomatic carriers, according to figures from the Guangdong Provincial Health Commission.

"While expanding screening for suspected patients and asymptomatic carriers, medical staff will spare no effort to cure them," Chen Bin, deputy director of Guangzhou's health commission, told a news conference in the city on Tuesday.

"When we detect positive results of nucleic acid tests during the mass testing campaign, the people suspected of being infected will immediately be sent to a designated hospital for further observation and treatment and medical experts will be organized for further group consultations."

Housing estates where positive results of nucleic acid tests are detected will immediately be put under control for further epidemiological investigation to trace the source of the virus and disinfect public venues to block the chain of infection, Chen said.

Guangzhou has now put 38 communities, most of them in its Liwan district, under lockdown to prevent and control the spread of the virus.

Chen said Guangzhou had collected more than 3.47 million swab samples in the past seven days.

She urged people to go out less and avoid attending parties to minimize their risk of being exposed to infection.

"Most of the cases were detected in Guangzhou's Liwan district and were infected with the coronavirus through family parties and close contact with confirmed cases in the previous weeks," Chen said.

To increase the city's capacity to administer nucleic acid tests, which are used to screen those suspected of being infected, a new laboratory started operation in Guangzhou on Tuesday. Built at the Guangzhou Gymnasium in Baiyun district by Guangzhou KingMed Diagnostics Group, it can test 30,000 samples a day, the company said in a statement released on Tuesday.

The laboratory is linked to Guangzhou KingMed's headquarters laboratory and includes areas for reagent preparation, sample processing and amplification analysis, it said. The laboratory can receive samples around the clock and issue results in six to 10 hours.

Guangzhou KingMed said it is also building three other laboratories to increase the city's nucleic acid testing capacity.

Cai Weiping, an infectious disease expert at Guangzhou No 8 People's Hospital, urged residents to get vaccinated against the novel coronavirus in a reasonable and orderly manner, as vaccines have played an important role in preventing and controlling the spread of the virus in the city.

"The results of clinical feedback have showed that the effect of our vaccines in the prevention of serious cases has been extremely outstanding," Cai said.

"All the locally transmitted confirmed cases and asymptomatic carriers in this round of outbreak in Guangzhou were diagnosed to be infected with the same coronavirus, which is similar to the mutated strains detected in India, and it has the characteristics of rapid transmission and strong transmissible capacity.

"Many patients' conditions would worsen in two to three days as the virus is very active. But the infected residents who have been vaccinated against COVID-19, including those who have yet to receive the second dose, are the patients with only light symptoms or asymptomatic carriers.

"The effect of the vaccines is obvious."

From Wednesday, Shenzhen Baoan International Airport will require passengers from Guangzhou and Foshan to show their green health codes and negative results of nucleic acid tests taken within 72 hours of boarding their planes.

On Monday, Guangzhou barred passengers unable to show green health codes and negative nucleic acid testing results from leaving the city by air, train or coach, and Foshan followed suit on Tuesday.