It was found that two negative samples and two positives samples were mixed up, resulting in two infected persons who were supposed to be sent to hospitals being sent home.

The two patients have since been transferred to the isolation wards in hospitals for treatment and are in stable condition, the HA said. Meanwhile, the other two people had returned home after waiting for the results in the test center at AsiaWorld-Expo.

The HA apologized for the inconvenience caused to the people affected, and expressed gratitude to all staff members in setting up the temporary test centers within such a short time, noting that lab technicians have been working hard in testing samples taken from arrivals.

Meanwhile, Chuang said that the authority has improved the distribution of wristbands at the airport to ensure all arrivals are given one upon arrival, regardless of whether they develop symptoms.

On Friday, arrivals with symptoms were sent to test centers, but were let go when they were tested negative to the virus without being asked to wear a smart wristband for monitor purpose during home quarantine.

Chuang said that arrivals who are subject to home quarantine should observe the rules and stay at their residences to avoid posing a risk to the community.

Despite the surge in number of confirmed infections, most of the cases were imported and traceable, Chuang said, adding that the city hasn't seen a community outbreak yet.

But she warned that more local cases without a traceable transmission chain could trigger a major outbreak.

Noting that the government is closely monitoring the situation, Chuang called on the public to stay vigilant and avoid any unnecessary social activities.