The apartment building boom is rolling on despite warnings of an overheated market according to the number of cranes on the skyline.

Where once most were on commercial projects, property and construction group Rider Levett Bucknall's (RLB) Crane Index for the second quarter found that the lion's share are now towering over housing sites.

The RLB Crane Index shows apartment developments are still strong. Credit:Jessica Shapiro

This trend is expected to continue as more large-scale non-residential developments are completed, such as Barangaroo South in Sydney, Southgate, Melbourne and the Commonwealth Games venues on the Gold Coast.

While the total number has slipped from the record 666 a year ago, there were still 330 new tower cranes erected across Australia's skylines in the past six months, offset by the removal of 342 cranes from projects nearing completion.