Whether it's keeping order on the streets or on the soccer pitch, Siu Ming-wai wants to be in control. As Hong Kong's only female internationally-licensed referee, most of Siu's work is done among male players, and the power to award a penalty or disallow a goal is not lost on her. 'On the pitch I can control 22 players,' Siu said. 'All, who are male.' Siu, 37, a constable in the crime department for the Hong Kong Police, is one of only four female referees in Hong Kong, but she doesn't think she is treated any differently. Being a member of the police force helps and many of the players know not to mess with her. Insults and verbal abuse are routinely hurled at officials? Not so, says Siu, who said most players did not swear at her. English international referee Mike Riley, who has worked many big matches including the 2002 FA Cup final and a controversial match between Arsenal and Manchester United in 2004, agreed that a person's sex did not seem to matter in officiating. 'It's about being a referee,' said Riley, who is officiating at the Soccer Sevens. 'If you're good enough it doesn't matter if you're male or female, because the players will accept you.' Riley cited English referee Wendy Toms, who moved through the England refereeing system and worked as an assistant referee in the Premier League from 1997-2005. The only problem, Riley said, was that in the latter part of her career Toms had difficulty with the fitness demands. 'Towards the end of her career she struggled to maintain the fitness standards, just like the guys do, but she's a brilliant referee and the players accepted her just as a referee.' Reaching the required fitness levels were difficult for Siu as well. Though she was the top scorer on her referees' written exam, she failed the fitness test the first time she took it. Her mentor, policeman and former referee Fong Yau-fat, said her drive to pass the fitness test helped prove her strength. 'She put in the hard work to learn to become a referee,' Fong said. 'When she became a referee, her fitness was not very good but with hard training she has become the best female referee.' Siu first became interested in officiating after she was constantly getting injured as a player. A fan of the sport since she was a child, Siu did not start playing until she was an adult and played alongside her work colleagues as the team's goalkeeper. But injuries, including broken hands, made her decide to take another direction in the sport. 'I like football, I wanted to continue with football and so [when] I had an opportunity to join the police football referee club, I took it,' Siu said. After passing her exams, Siu officiated at third division matches and was promoted to the second division a year later. Another promotion to the first division followed and Siu aims to one day officiate in the women's world cup. In her short career, Siu said she was most proud of her invitation to officiate an international match in India. The experience was initially worrying - not only did she not know what the procedures were for going overseas, but she had to convince her husband and eight-year-old daughter, Kitty, to let her go. 'I spent a lot of time convincing my family,' Siu said. 'My husband and my daughter didn't want me to go at first. Luckily, I convinced them.' She has since turned down an opportunity in Thailand because of her family and last summer she rejected another offer because she could not take leave from her work. Siu says her part-time job as a ref has a lot in common with her everyday work. 'In the police you need to emphasise discipline and team work,' Siu said. 'We are trained to handle some emergency events, so it is a great help to the referees. On the pitch I need to control so many players. I need to control their tempers and emphasise teamwork. It is the same as police work.'