Planning Minister Matthew Guy has been dubbed ''Mr Skyscraper'' after approving 20 high-rise developments for inner Melbourne and rejecting just one since taking on the portfolio about two years ago.

Mr Guy announced on Monday that he had approved plans for the tallest tower in the southern hemisphere - Australia 108 - which will stand at 388 metres and be 90 metres higher than Eureka Tower.

His decision to approve the Fender Katsalidis-designed apartment project on Southbank Boulevard will upset critics of the plan, including Melbourne lord mayor Robert Doyle, who argued it would cast a shadow over the Shrine of Remembrance.

The latest permit caps 19 other approvals Mr Guy has issued for tower projects in the Melbourne CBD and inner suburbs that range from 19 to 71 storeys high, since the Coalition won the 2010 election. He has also rezoned swaths of land at Fishermans Bend, Footscray and North Melbourne for high-rise development.