He tendered his resignation on Monday after attending the 53rd birthday party of Witman Hung Wai-man, principal liaison officer for Hong Kong at the Shenzhen Qianhai Authority and a Hong Kong deputy to the National People's Congress, on January 3 at a Wan Chai restaurant amid the local outbreak of the highly infectious Covid-19 Omicron variant.

Given his term was supposed to last till June 30, his early exit costs him five months of salaries – which is more than HK$1.9 million, based on his current monthly salary of HK$391,166.

But his profits from property investments can well cover his lost salaries.

Tsui and her wife owned a number of properties, including two flats and two parking spaces at Parc Oasis in Kowloon Tong.

The two sold a flat of more than 800 square feet and two parking spaces in the past three months, cashing in HK$17.51 million and making a profit of HK$6.475 million.

Tsui has been with the government for nearly 14 years, first as political assistant to Secretary for Home Affairs then Undersecretary for Labour and Welfare. He was promoted to Secretary for Home Affairs last year - the youngest secretary in the current administration, and the first secretary who started off as a political assistant.

Back in 2017 when Tsui was the Undersecretary for Labour and Welfare, he failed to spell the minimum wage level when asked by a reporter, and had to pass the question to Secretary for Labour and Welfare Law Chi-kwong.

In 2020, he uploaded a photo of a sweet soup on the day that a fatal fire broke out in Yau Ma Tei. He was criticized by netizens for enjoying himself while people's lives were at stake, but he replied later that it was "multitasking".