It was not immediately known how many workers were trapped, state-run Xinhua news agency reported.
The market for home furnishings and building materials in Qiaokou district of the provincial capital Wuhan collapsed during construction this morning, fire brigade officials said.
Xinhua reporters at the scene said the cave-in happened in the underground structure, seemingly a garage, that covered about 300 square meters and was two-storey high.
At least two people were seen injured after they were pulled out of the rubble, said a witness surnamed Song.
Song, who lives near the construction site, said she felt the tremor when the construction caved in.
"It lasted about 10 seconds," she said.
Several residents said they saw more trucks than usual carrying cement to the site last night, a sign that construction had been accelerated.
Rescuers were still searching for survivors in the rubble with life detectors.
