The damage was caused by large hail which pelted the northwest and northeastern suburbs. The areas of Taylors Lakes, Keilor, Eltham, Greensborough and Keilor Downs were the hardest hit.
Fifteen of the 20 emergency calls relating to flash flooding came from Eltham.
Mr Quick said the hail had punched holes in roofs, skylights and windows, leaving buildings more exposed to the ensuing round of storms.
"The next four of five thunderstorms that swept through have all hit the same areas, unfortunately, which meant there was a lot more building damage as a result of the holes already punched in those buildings,'' he said.
"I'd anticipate the clean-up to take at least two days, if not longer, simply because of the sheer number of jobs and type of damage.''
The SES, which yesterday relied on 250-300 volunteers, also had to rescue people from 20 cars caught up in the flash-flooding of roads during the storms.
Strong winds and lightning forced the diversion of international and domestic flights at Melbourne Airport, while planes that had been due to fly out were grounded.
Early on Monday moderate flood warnings were in place for the Merri Creek at Coburg, in Melbourne's north, and for the Watts River at Healesville.
The Bureau of Meteorology was predicting drizzle with a top of 23C for Melbourne for the start of the Boxing Day Test at the MCG.
The chance of thunderstorms over the eastern suburbs was forecast for early in the morning, with sunny breaks mid-afternoon.
- AAP
