One week after the nation's biggest road infrastructure project opened to the public, the NSW government is busy "jiggling and juggling" final traffic tests ahead of the real WestConnex stress test — the end of school holidays.

Key points: Transport experts are concerned extra citybound traffic could back up into the tunnels

Transport experts are concerned extra citybound traffic could back up into the tunnels Police, transport commanders and tow trucks will be on hand Monday to smooth the traffic flow

Police, transport commanders and tow trucks will be on hand Monday to smooth the traffic flow The entire Westconnex, linking the M4 and M5 motorways, is due for completion in 2023

Sydney's M4 East tunnels opened to drivers last Saturday, with the twin tunnels connecting Homebush and Haberfield at the price of $4.27 per trip.

The new traffic conditions created confusion for some, with motorists caught on camera stopping and reversing in the wrong lanes at the Haberfield entrance.

The coordinator-general for Transport for NSW, Marg Prendergast, said while the opening had overwhelmingly been smooth, focus was on traffic hotspots ahead of Monday's rush hour.

"Opening when it was school holidays, that was deliberate, because we know that it takes people a while to get used to such a big piece of infrastructure," she said.

Ms Prendergast said the real worry was how increased traffic would flow out of the tunnel when school returned on Monday.

"We're going to be focused on where people are heading citybound and merging at Parramatta Road, Ashfield and City-West Link, Wattle Street, and that's because that's where the traffic merges and we're worried about potentially backing up into the tunnels," she said.

Marg Prendergast says it takes time for people to adapt to new infrastructure. ( ABC Radio Sydney: Harriet Tatham )

Traffic relief still a way off

In conjunction with NSW Police, the Transport NSW will have more than 250 people in the field on Monday morning to help smooth the opening, including transport commanders, incident report vehicles, tow trucks and people who can change signals to allow for longer green lights in real time.

In spite of these resources, ultimate traffic relief will have to wait.

"For the next few weeks we're going to be jiggling and juggling and working out these different travel patterns and seeing what we can to smooth the flow for everyone," Ms Prendergast said.

"But ultimately, it's the [yet to be built] M4-M5 link, the Rozelle interchange and the Western Harbour Tunnel that will bring ultimate relief."

The project's proposed M4-M5 link, which will create a non-stop bypass underneath the western edge of the Sydney CBD and inner-west, won't come for another four years.

But drivers exiting the tunnels at the City-West Link were impressed with stage one.

WestConnex saved Chicco Boustani 10 minutes on his trip from Blacktown. ( ABC Radio Sydney: Harriet Tatham )

"It was actually really good," said truck driver Chicco Boustani, who was travelling citybound from Blacktown.

"It saved me 10 minutes, give or take, so hopefully by the time the rest of it is finished it might be worthwhile."

Picnic Point commuter Majed Odeh agreed.

"The traffic is trickling off WestConnex — it's good."

Eventually, WestConnex will link the M4 Motorway to the M5 Motorway, CBD and airport via 33 kilometres of tunnels and motorways — a project the NSW Government said would enable motorists to bypass 52 sets of traffic lights between Beverly Hills and Parramatta.

The entire project is slated for completion in 2023.