The accident was reported from the capital city BPTP building situated in sector 94, Noida. Five other workers sustained serious injuries after they were buried under the wreck of the shuttering.
The Police and rescue teams rushed to the spot and extracted the people stranded under the iron grills.
A police official said prima facie, it appears that the shuttering was hit by a tractor-trolley carrying construction material, which led to the incident but the cause is yet to be ascertained.
"Nine people were injured when the shuttering of the building collapsed. Four of them have died, while five others have been hospitalised," Senior Superintendent of Police, Gautam Buddh Nagar, Ajay Pal Sharma said.
An FIR has been registered at the Sector 39 police station, under whose jurisdiction the building is located, police said.
The deceased have been identified as tractor-troller driver Naushad and workers Karan, Vijaypal and Ramvijay, they said. The injured, Ajay, Shadaab, Mahesh, Nisaarul and Ashok, are undergoing treatment at local hospitals, they added.
(With inputs from agencies)