It took seven months to design and install the panels,which are 191 metres above street level,with the strong winds that buffet the top of the tower posing a major engineering challenge.
The general manager of 101 Collins,Peter Calwell,said a 7.75-metre steel structure had to be constructed to hold the panels in place.
"We didn't want them floating down Collins Street,"Mr Calwell said.
"There's not a lot of obstacles between the prevailing wind and the top of the building,which is great from the point of view of the panels because it means nothing is going to block the sunlight."
Engineering services manager Bill Burgess said the highest recorded wind speed was 121km/h.
It is not the first time the roof of 101 Collins has been put to a practical use. The mast of the 56-level building hosts a number of telecommunication facilities,including for emergency services,while Channel Seven has a camera perched on the south side for a bird's-eye view of the Australian Open.
The $230,000 solar installation will produce about 47,000 kilowatt hours of energy each year,equal to the annual energy use of about 12 homes.