Users of Pink Dollar will rate businesses on their "gay friendliness"

A smartphone app that aims to connect gay-friendly businesses with lesbian, gay, bisexual and transgender customers has launched in Hong Kong.

Businesses apply to be listed on the Pink Dollar app and are then rated by the customers.

Initially the app will be available only on Apple iPhones. An Android version is planned.

The app was created by British entrepreneur Paul Ramscar, who lives in Hong Kong.

"It's not just an app, there is a bigger cause here," he said.

"Having lived in Europe, the culture was very open.

"You can be open, be free, walking around holding hands, there are no problems. In Hong Kong you can't really do that."

Laura Doughty, deputy chief executive of gay rights campaign group Stonewall, said technology played an important part in connecting lesbian, gay, bisexual and transgender people.

"The internet has made it much easier for gay people to find resources and use them, whether that's gay-friendly businesses or networking opportunities," she told the BBC.

"You'll probably see more of it - not only in the dating area, although that's key too. The 'pink pound' is valued at £81bn in the UK alone."

Since its launch in 2009, more than four million people worldwide have used the smartphone app Grindr, a location-based gay dating network.

This year the company launched an equality campaign, sending messages to users about events in their locality.

"Simply put, let's use Grindr to organise and fight for our rights," it said.

BBC News Technology