A police report said that the accident happened at 11am. The crane, which was being manoeuvred by a 57-year-old man from Swieqi, toppled over and hit the man.
He was rushed to hospital where he was found to be in a critical condition. Later, his condition was reported to be stable.
Duty Magistrate Dr Joseph Apap Bologna was informed about the incident and appointed several experts to draw up a report.
The Birkirkara police are investigating.