Rozelle Interchange to open for Sydney drivers on Sunday morning

Sydney's new mammoth underground road project, the Rozelle Interchange, is scheduled to open in the early hours of Sunday morning. 

The NSW government on Friday afternoon confirmed that the multi billion-dollar tunnel network in the city's inner west would be open to the public this weekend. 

It comes four years after construction began on one of the most complicated underground interchanges ever built, with 100,000 drivers expected to use it on their daily route. 

The interchange is the final piece in the WestConnex motorway's promise to deliver a 20-minute saving on travel time between the CBD and Parramatta.

Some 24 kilometres of tunnels connect the City West Link, the Iron Cove Bridge, the Anzac Bridge and the M4-M8 Link between St Peters and Haberfield. 

Drivers have been assured that navigating the weaving web will be simple enough by following the signs, with only one of two optional routes available at any given time.

Over the four years, 20,000 construction workers have been involved in the project. 

Some of the sections of the tunnel system run 20 storeys deep, and feature 1.74 million metres of electrical cabling, 7,400 lights and 132 jet fans. 

Six and a half million tonnes of rock and soil had to be excavated in order to dig the tunnels.

Project director Steve Keyser said bringing together a project of this size presented a great challenge. 

"We peaked at probably about six or seven hundred workers at once, working 24/7 underground, 23 road headers," he said.

While the project has, incredibly, been delivered on-time, local residents were often up-in-arms along the way. 

Homes were compulsorily acquired, and some residents complained of unbearable noise around the clock as tunnel boring machines drilled underneath them. 

Controversy also swirled around a trio of large exhaust smokestacks sitting where the WestConnex motorway will meet the Anzac Bridge.   

The finished product also looks very different to the state government's initial proposal, which featured large surface ramps crisscrossing each other. 

Transport NSW coordinator general Howard Collins said drivers would have plenty of warning and clear signposts along the way. 

He is also confident ventilation and monitoring systems are well-equipped to handle any hazards, if they were to occur. 

"We have the latest technology, over 800 cameras, we've got crews on stand-by literally ready to go if there's any incidents in the tunnels," he said.