A firefighter battles the flames at the Barangaroo worksite.

A firefighter battles the flames at the Barangaroo worksite on Wednesday. Photo: Chris Pearce

A team of 30 safety inspectors will launch a blitz on major building sites in response to the Barangaroo fire and other major workplace accidents.

John Watson, the general manager for workplace health and safety at WorkCover NSW, said the six-week sweep of commercial construction sites would include Sydney and particular hot spots in regional NSW.

''This is in response to three high-profile incidents, including the Barangaroo fire, the tower crane fire at the UTS building and the collapse of scaffolding at O'Riordan Street in Mascot,'' Mr Watson said.

A smoke plume rises from the Barangaroo site.

A smoke plume rises from the site. Photo: Nic Walker

''The blitz will target the commercial building sector, particularly looking at multi-level construction.

''It will look at a range of issues, including scaffolding, emergency evacuation cranes, excavations and working at heights. It will also look at hot works [such as welding] to ensure appropriate emergency equipment is used.''

Mr Watson said WorkCover would meet with major contractors next week to inform them of the blitz.

Barangaroo worksite. Click for more photos

Barangaroo on fire

Barangaroo worksite. Photo: Chris Pearce

He said the meeting would ensure ''all the major contractors understand they are on notice of making sure they actively manage workplace health and safety at each of their sites''.

''We have inspectors on the ground today starting to conduct visits and we anticipate that inspectors will use the full range of regulatory approaches we have, including improvement notices, prohibition notices and will provide advice on how to address low-risk issues,'' Mr Watson said.

Unions NSW called for an urgent safety review of all building sites following Wednesday's blaze at the Barangaroo construction site on Sydney Harbour.

The fire, which took nearly 24 hours to extinguish, forced 2000 people to evacuate nearby buildings and closed surrounding roads for hours due to fears a 20-storey crane would topple. It was the second fire on a Lend Lease construction site in 18 months.

A crane caught fire at a UTS building site at Broadway in November 2012, and three people were injured when scaffolding collapsed at a Mascot site two weeks ago.

Unions NSW secretary Mark Lennon said the blitz was a ''positive step'', but a more comprehensive audit was needed to identify and rectify any systemic safety problems in the building industry.

He said the audit should address not only the safety of equipment but also whether principal contractors were ensuring subcontractors met occupational health and safety obligations.

The NSW secretary of the CFMEU, Brian Parker, said he was happy WorkCover had announced a blitz, but said it should run for 12 months to ensure builders were kept ''under the microscope''.

''The six-week period is only a Band-Aid solution,'' he said.

Emergency crews have handed the Barangaroo site back to Lend Lease.