Mr Li is one of 59 mainland exhibitors at the fair who is reaping the benefits from the growing popularity of mainland books in Hong Kong.

While the low prices are one reason why people find the books more attractive, an improvement in print quality and a wider selection of titles have also helped boost sales.

'I think our most competitive advantage is price,' said Jiang Min, of Shanghai Book Traders, '[and] then comes content.'

Mainland books cost a fraction of Hong Kong titles, with many selling for $10 to $30, with topics from calligraphy to politics, history and music.

Ms Jiang said her company has been trying to break into Hong Kong's market as its first consumer penetration target outside the mainland. Her best-sellers last year were music books.

'Hong Kong people have a very good reading culture,' she said. 'They love to read.'

Calvin Li Hon-ming, business development manager of Sino-Books, said greater interaction between the mainland and Hong Kong people also made some locals feel the need to learn more about people and places across the border.

His company has been distributing mainland titles to Hong Kong for the past two years. The book fair has been one way to promote them.

He brought mainstream and practical lifestyle and health-related titles to this year's fair.

He also said that the market conditions at the fair had changed.

'Before we were only here to exhibit and brought only one or two copies of the books,' he said. 'But now we are here as sellers.'

One of the more expensive titles from mainland publishers was a box set commemorating the 100th birthday of late leader Deng Xiaoping.

It includes a CD, a book of stamps, photographs and voice recordings from the former leader. Retail prices start at $1,100 but it is sold at a discount from $600 to $980.