A glass panel shattered on the ninth-floor balcony of a South Melbourne residential tower on Thursday evening, showering glass shards onto the pavement and narrowly missing pedestrians.

Simon Kerr was walking along Albert Road with his partner about 6.30pm when he heard a loud cracking noise from the Emerald building. Within seconds, fragments of glass had rained down in front of him.

A glass balcony explosion narrowly missed pedestrians in South Melbourne's Albert Road. Credit:Simon Kerr

"Another 10 seconds or so and we would have been directly underneath it," the 45-year-old IT worker said.

It remains a mystery as to why the glass fell, but an investigation by The Age in 2017 revealed a series of spontaneous glass balcony explosions in Melbourne apartment buildings that were believed to be linked to the rise of poorly manufactured imported glass.