Barangaroo fire sparks WorkCover blitz

A fire at Sydney's Barangaroo development and calamities at two other construction sites have sparked a WorkCover blitz on high-rise building projects across NSW.

Contractors and developers will be grilled during the operation, with "high risk" items and activities including scaffolding, cranes, hoardings and welding under examination.

It follows a series of worrying incidents at building sites, including Wednesday's fire at Barangaroo, which threatened to topple a crane.

The blaze at the Lend Lease project was put out on Thursday, with the crane to be dismantled as a precaution.

An investigation into the cause of the blaze is underway, with one theory blaming a welding torch.

The Barangaroo area is being redeveloped as a residential and retail hub, with plans for a high-rollers' casino owned by billionaire James Packer.

A Lend Lease crane did collapse during a fire at the University of Technology Sydney at Ultimo in late 2012.

And in another incident, two people were injured when scaffolding collapsed at a building site in Mascot, Sydney's south, in February.

WorkCover health and safety manager John Watson said the incidents were not linked.

The blitz will include some regional work sites.

The Construction, Forestry, Mining and Energy Union (CFMEU) said the blitz was a "positive move forward" but wouldn't be effective unless it ran for at least a year.

"A building site would change a number of times over the course of a year and in many cases safety issues become more paramount as developments increase in height and scope," CFMEU NSW secretary Brian Parker said in a statement.

Mr Parker also raised concerns about whether WorkCover had "the expertise and staff to do this job."