The Office of the Privacy Commissioner for Personal Data (PCPD) on Thursday reminded employers and managers not to spread employees' personal data when handling sick leave arrangements.

The reminder came after the privacy watchdog saw an increase in complaints related to the mishandling of employees' personal data, with the number rising from 89 last year to 103 this year.

The PCPD said most of the complaints involved the unnecessary disclosure of employees' sick leave details, including their illnesses, noting that one of the complaints involved a manager at Kwong Wah Hospital sharing details of an employee's sickness with colleagues in a group chat.

At a press briefing, Privacy Commissioner Ada Chung called on employers and managers to protect the personal data of their workers in accordance with legal requirements.

"There is no need at all for the employers, or for HR managers, to disclose the physical conditions of the employees in question to other workers," she said.

The commissioner also called on the online marketplace Carousell to beef up its data protection efforts following a leak last year affecting more than 320,000 users in Hong Kong.

Chung said the PCPD's probe into the leak, which affected 2.6 million users worldwide, revealed that the platform had failed to implement preventative measures before a data migration procedure.

She added that her office has issued a notice to Carousell, urging it to proactively monitor abnormal activities on its platform and prioritise user privacy protection.

"We have already issued an enforcement notice to the company in question, asking them to take a number of measures to safeguard the personal data of Carousell users in Hong Kong... I have also requested them to engage an independent cyber security expert to examine the whole system to ensure that there is no similar coding error or known vulnerability," she said.

Carousell was given two months to comply with the notice issued by the PCPD.