The condemnation by the all-party House of Commons Transport, Local Government and the Regions Committee follows three system failures in recent months.
The committee also warned that Nats' IT systems are "not sufficiently robust to enable it to reduce the number of safety-critical staff''.
"Air traffic control assistants are vital to the safe operation of air traffic control, and it is incredible that Nats intends to reduce their number so soon after moving into a new, highly complex operating environment," it said. "It is essential that Nats and the Civil Aviation Authority clearly demonstrate a substantially greater level of robustness in computer equipment at Swanwick before embarking on the planned reductions."
The report also revealed that in January this year the Health and Safety Executive assessed display screen equipment at Swanwick and identified "concerns relating to the clarity and readability of certain information on the display screens and to the design of keyboards and workstations''.