It appears scaffolding which was loosened when wet and windy storms hit the NSW Hunter region this week caused the death of a male worker.
The 73-year-old fell to his death at a residential site in Maryville after the mobile scaffolding he was working on slipped from under him, SafeWork NSW says.
Another 62-year-old man also suffered head injuries a day earlier after he fell two metres from a ladder while cleaning roof gutters in Balgowlah.
A construction site in Lane Cove, on Sydney's lower north shore, was also investigated by WorkSafe NSW inspectors after two bays of scaffolding collapsed onto the Pacific Highway during demolition work.
Construction workers have been urged to remain vigilant while working in wet and windy conditions.
"High gusts of winds are unpredictable and cause a range of serious workplace hazards associated with flying objects, working at heights and an increased risk of collapsed structures," SafeWork NSW Executive Director Peter Dunphy said.
He said slippery surfaces should be avoided where possible, and workers shouldn't stand too close to loads, trees and overheard powerlines.
"Wind speeds are often stronger and faster at heights, so operating cranes or using powered access platforms require additional caution," he said.