Demand for Hong Kong's new 24-hour mental health support hotline which launched this week will be "huge", a psychiatrist said on Thursday.

The government says around 20 organisations are linked to the 18111 hotline and callers will be referred to the most appropriate group, depending on their needs.

May Lam, founder and president of the Hong Kong Mental Wellness Association, said having a single place to turn to will make it easier for people to get help.

"There are a lot of services in the community, but sometimes, it’s not that easy for people to get access, or to know about the number.... I think if there is one hotline, if it can cope with the demand, or the government has a plan to address the demand if it’s increasing or it’s huge, I think it’s a convenient way for people to approach initial help," Lam told RTHK.

"I believe the demand will actually be huge. I think if people know about the hotline, and it’s one number, easy to remember, I really believe that the demand will actually be quite large."

The NGO commissioned by the government to operate the hotline, the Richmond Fellowship of Hong Kong, said it aims to answer all calls immediately, as this is what people will expect.

"They may feel uncomfortable if they have to wait a long time to get through, especially for those who are already in a bad mood," the group's director, Fung Cheung-tim, told Commercial Radio.

Officials say people who don't get through immediately will receive a call back from hotline staff within 30 minutes.