The Federation of Trade Unions (FTU) called on Wednesday for more efforts to promote lesser-known heritage sites in Hong Kong after one of its studies found that the city's cultural tourism potential remains largely untapped.

The federation, in a poll of more than 400 mainland tourists in November and December, found that nearly half were unaware of major historical landmarks on Hong Kong Island.

Lawmaker Kwok Wai-keung said travellers need a new mobile app to tell them where to go.

"As we know, tourism is a core industry of Hong Kong, so we have to put more information on the internet and let people know more about our culture," he told RTHK.

"The one-stop platform should provide more information and also some transportation methods so that [tourists] can have a walk around parts of the city and try the local food."

Noting that 80 percent of respondents would visit a place because of a book, the federation suggested developing creative themed tours based on literary heritage.

It also urged the government to better preserve local heritage, including neon signs and traditional shops.