In a further sign the construction phase in Sydney and Melbourne is slowing, the number of cranes in both cities is down with projects stalling due to economic uncertainty.

While some cranes are shifting to the other previously laggard cities of Perth and Brisbane, the overall national number has dropped by 5 per cent, according to the latest Rider Levett Bucknall (RLB) Crane Index covering the six months ending March 31.

RLB Oceania director of research and development Domenic Schiafone said pre-contract project work had been frozen, due to the uncertainty over when government restrictions due to the coronavirus pandemic would end.

The number of construction cranes across the country has declined. Credit:Steven Siewart

"Projects across most sectors, in the design phase, have virtually been put on hold," Mr Schiafone said.