The 29-year-old may only be part-time for now, but she drew plenty of attention since she appeared as the fourth official in top league matches last season.

Law has been an official for four years, and she is now a top (Class One) referee in women's football and is a second class referee (Class Two) in men's football for the Hong Kong Football Association (HKFA).

She has no fear refereeing men's games and can take the flak from fans - and she says her femininity tends to work for her rather than against her, recalling only one unsavory incident.

"There was only one time that things turned ugly," said Law.

"It happened in a third division match some years ago. A player who did not agree with my ruling attacked me by throwing a ball at my chest. The association later punished him.

"But that was an exceptional case," said Law. "I feel grateful that I am doing the job in Hong Kong, as most players in the city are gentlemen.

"I know girls in some Asian countries don't have the chance to be in charge of a men's game, as their associations think it is way too dangerous and don't believe they can control players."

HKFA referees manager Charles Cheung Yim-yau heaped praise on Law.

"Gigi is outstanding among the women's referees in Hong Kong, and is above average in the men's system," said Cheung.

"Unlike some other women's referees who may have fitness problems from time to time, Gigi has never failed her fitness tests [ which are held every six months] since she became a referee at the association.

"She is a brave lady, and with her excellent fitness, knowledge in football and experience as a player at tertiary schools level, she fits the referee job well."

Law is at the halfway point to one of her goals - refereeing at the 2019 Women's World Cup. This month, she took exams to join the panel of referees at the Asian Football Confederation.

Cheung said Law had proved her ability as she qualified for the course with a male referee, Ho Wai-sing - the first time for Hong Kong to have referees on the course under the new system adopted by the AFC two years ago.

Law and Ho are awaiting their results, but Cheung said only the strongest candidates would stay in the course for further training, and the most gifted were given the chance to become a panel referee directly.

"Getting this qualification will allow me to take charge of more international matches," Law said. "At every Women's World Cup they nominate some referees to represent the continent.

"Hopefully, my performance will impress them to include me for the World Cup referee squad. It will also prove that Hong Kong football has reached a certain level, as referees also need to practise in intense matches to grow and become familiar with the duties," said Law.

A sports fanatic, Law was a student athlete in volleyball and cross-country before she decided to take the foundation course and then the higher-diploma course in sports management and training science at the Hong Kong Institute of Vocational Education (IVE).

"I played volleyball and I am also a referee for the sport. But I didn't have volleyball among the options for major sports when I was studying at IVE, so I chose football as my major sport and got a D grade-coaching certificate from the HKFA. My endurance was spotted by teachers and I started to learn and try refereeing," said Law.

She then finished a top-up degree and worked in the sports public relations industry while studying for her postgraduate diploma in physical education and mathematics at the Hong Kong Institute of Education (HKIEd).

"I found refereeing enjoyable and I am not into those typical spare-time activities for Hong Kong girls," said Law.

"But maybe this is also why not many girls pursue a referee's job in Hong Kong. It is physically demanding and, on top of that, it is also tough to ask girls to give up their weekend of shopping, hanging out or dating. When you have kids, you will also be occupied on family days," said Law.

According to Cheung, the HKFA has around 290 active registered referees in all classes.

There are only five women, including Law. Three are new referees and the other one is a Class Three referee.

Law said she was a friend of many players as well as a supporter of various league teams and was more than happy to take encouragement - and criticism - from them.

"The fans are friendly. I always talk to them after a match and they ask frequently when will I be in charge of a [Hong Kong] Premier League match," said Law.

"Even HKFA chairman [Brian] Leung Hung-tak asked me to take the Class One referee test as soon as possible to become the first lady to referee in the top league."

She is preparing for a fitness test, which has the same requirement for men and women, to become a Class One referee for a men's match.

The fitness test includes six 40m sprints, which needed to be completed within six seconds each with one-and-a-half minutes rest in between each. Another assessment is the interval run. Candidates need to finish 4,000m non-stop by running intervals of 150m in 30 seconds and then walk 50m in 40 seconds.

The qualification will elevate her from her current position to assistant official and eventually the main official with the whistle.

Off the pitch, Law is also keeping busy. She received her teaching accreditation from the Education Bureau this month and can become a supply teacher. She has also signed with an agent to help her get promotional jobs.

"There are also women's football referees in South Korea involved in other businesses, who have proved to be a success. I hope to build up a healthy image for referees through different channels," said Law.