Ma Lik (
"He died at 2pm this afternoon," Lam Yau-fau, a DAB official, said.
DAB Vice Chairman Ip Kwok-him (
Local media reported that Ma's condition worsened after he contracted pneumonia, and that he had fallen into a coma and was breathing through a machine.
Ma announced he was suffering from colon cancer in August 2004, just weeks before he successfully ran for a legislative seat.
DAB said later that month he had undergone successful surgery, and since then he has been traveling between Hong Kong and Guangzhou for treatment.
Although he also serves as a Hong Kong delegate to China's legislature, the National People's Congress, Ma was not known as an outspoken pro-Beijing hardliner. But he triggered a major backlash in May when he questioned whether the Chinese crackdown on protesters in Beijing's Tiananmen Square in June 1989 was a "massacre."
Hong Kongers are still sensitive about the crackdown, which occurred before the then-British colony's handover to Beijing.
Ma left for treatment in Guangzhou immediately after his Tiananmen Square comments and did not return to Hong Kong.
He missed the official festivities marking Hong Kong's 10th anniversary under Chinese rule, which were attended by Chinese President Hu Jintao (
Ma took over as DAB leader from Tsang Yok-sing (