The fire broke out just before midnight at the packed King of the Dancers club, sparked by a pyrotechnics display on the third floor, said Xinhua, quoting local police as saying.
The owner of the club, located in a blue collar area about an hour's taxi ride from downtown Shenzhen, was being questioned by police, but no charges had yet be filed, said Xinhua.
The main hall quickly filled with deadly smoke after the roman candle-type display touched ceiling tiles, and the lights went off soon after -- plunging panicking revellers into darkness, said witnesses.
"The fire wasn't that big, but there was a lot of smoke," said a man surnamed Zhang, who said he worked at the club.
"Everyone was crowding towards the front entrance, because they didn't know about the one in the back," said Zhang.
"We tried to tell them, but nobody would listen," he said.
Just hours later a coal mine gas accident in central Henan Province claimed 37 lives, said Xinhua.
Rescue efforts are underway at the privately-owned mine, which had 108 miners underground at the time of the accident, 64 of which were able to escape, it said.
China is trying close smaller unsafe mines, but with soaring coal prices mine operators working in concert with local officials have strong financial incentives to keep their mines open.
The accidents come as China is scrambling to contain a spreading scandal over tainted dairy products that has killed four children, made thousands more ill, triggered a regionwide recall and sparked an outcry from China's trading partners.
Premier Wen Jiabao presided over a cabinet meeting last week, after which the government said the incident reflected chaotic industry conditions, loopholes in the supervision and management of the dairy industry.
Many of the deaths and injuries occurred in a stampede to escape through a narrow hallway, said Xinhua.
The Party chief of the province, Wang Yang, has ordered an immediate investigation into the cause of the accident, said Xinhua, without giving any other details.
