Government officials have said the flood was triggered when workers digging tunnels broke through into an old shaft filled with water.
More than 100 workers were able to escape as the floodwaters rushed in but the rest were trapped underground.
Miners who had escaped told the Reuters news agency that the number of trapped miners given by authorities was too low.
"We sent 10 tramcars down to the pit before the flooding and each car usually carries 44 miners and a driver," a tramcar driver who was working on the day of the accident said.
"Only one car came back up the shaft, plus a few dozen miners who escaped on foot."
If true, nearly 450 people could have been underground at the time of the flood.
Al Jazeera's Harry Fawcett, reporting from the mine site, said the mining company had been criticised for not taking necessary security measures.
"At the weekend, miners were saying the usual dust produced by digging simply wasn't happening and they could see water seeping in," he said.
"It seems that they did report this to managers but work just went on as before."
The Wangjialing mine is a prominent project belonging to a joint venture between China National Coal Group and Shanxi Coking Coal Group, two of the country's larger state-owned companies.
|China's coal mines are the world's deadliest, despite efforts to reduce fatalities [Reuters]
China's coal mines are the world's deadliest, despite government efforts to reduce fatalities.
Most accidents are blamed on failure to follow safety rules or lack of required ventilation, fire controls and equipment.
Accidents killed 2,631 coal miners in China last year, down from 6,995 deaths in 2002, the most dangerous year on record, according to the State Administration of Coal Mine Safety.
David Faikurt, a mine safety expert and adviser to the Chinese government and coal industry, said the government had introduced regulations in an effort to help reduce the frequency of accidents.
"Every mining company, once they build a new mine, must have a risk assessment plan before they even start digging the hole," he told Al Jazeera from Beijing on Friday.
"One of the problems is that this is a bit of a desk exercise," said Faikurt.
"There is not a system in place which carries out a risk assessment on a daily basis, so that every miner, on every shift, and every supervisor, can be part of it and can be alert for the kind of situation that developed [at Wangjialing]."