Police identified the dead as Ghanshyam Khanna, the contractor and Sipahi, one of the labourers.
Two other workers, Mukesh and Hardayal, have been admitted to hospital.
A few more workers are feared trapped under the debris and rescue efforts are on, police said on Saturday evening.
More than 50 labourers were working in the building. Most of them were on the first floor when the incident took place.
Five to six labourers were on the ground floor and were buried under the debris when the building collapsed, police said.
Police said the owner of the factory, R Gupta, was getting the building constructed without the mandatory approval from the authorities concerned.
Principal Medical Officer O P Mehta told Newsline, “Two persons have died in the building collapse and two others have been injured. One of the injured has been referred to Safdarjung Hospital in Delhi”.
Haryana Labour Minister Shiv Charan Lal Sharma and other government officials visited the spot around 4.30 pm. Sharma told reporters that the builder did not have necessary approval.
Sources said work on one of the rooms in the ground floor had not been done properly.
Ignoring this, the contractor went ahead with the construction of the first floor, which could have led to the collapse, sources said.
“Most of the labourers were on the first floor and there were about five
men on the ground floor. When the building collapsed, those on the ground floor had no chance of escaping,” Tinku, one of the labourers, said.
“The prime focus on Saturday was to rescue those caught in the debris. We will register a case and arrest the building owner later,” Deputy Commissioner Balraj Singh said.
Officials said an inquiry will be conducted by different agencies, including the district administration and the Labour department.
The Labour ministry will provide compensation to the families of the victims, a district administration official said.