Fair director Wilson Tong said the expo's location called into question whether Hong Kong was as progressive as it made itself out to be.

'Sex is still a taboo subject in Hong Kong,' Tong said. 'For four years, Shenzhen held a Sex Culture Festival to promote sex education, health and family planning.'

Tong said the Hong Kong Convention and Exhibition Centre preferred to avoid more 'racy and adventurous' events like the Asia Adult Expo.

'Lack of knowledge and an outdated stance towards this type of event is the main problem,' Tong said. 'The exhibition centre forbids adult expos from being held in Hong Kong, because they don't fully understand how beneficial they can be.'

Apart from the event's educational value, Tong believed it also provided a chance to 'discuss openly so-called taboo subjects'. From a business point of view, he emphasised the missed opportunities.

'When it comes to the international trade of adult products, Hong Kong leads the way in Asia by exporting the largest volume of adult products to Europe and the US,' he said.

Successful manufacturers of adult clothing and entertainment products in Hong Kong include Electric Lingerie, Hop Shing Toys Factory and Loewie.

Tong said the convention centre's lack of in-depth knowledge on the subject was hindering the industry's development.

'Their traditional misunderstanding is now forcing the trade to be moved to Hong Kong's neighbouring cities like Macau, Shenzhen, Taiwan and even Singapore,' he said.

The Venetian Macau hosted another Asia Adult Expo in August.

The Hong Kong convention centre maintained that the only reason the Asia Adult Expo had not yet appeared in the city was because of the lack of venue space.