Tsang is widely expected to coast to victory. China's leadership has praised Tsang, and his public approval ratings have been high amid an economic upturn.

Standing in front of a massive sign with the slogan "I'll get the job done," Tsang said in a televised news conference that he would seek another term.

"Like many Hong Kong people, I will not be satisfied with the present," he said. "I want to do my best in everything. I truly hope we could work together to advance Hong Kong to an improved new world."

He is running against Alan Leong, a pro-democracy lawmaker and lawyer.

Tsang -- a veteran civil servant -- is Hong Kong's second chief executive since the former British colony was returned to China 10 years ago.

He took over from Tung Chee-hwa, who resigned in 2005 midway through his second term. Tung said he was quitting because of failing health.