On the eve of the opening of the Sydney Gateway, the New South Wales government has assured commuters it will not be a repeat of the disastrous opening of the Rozelle Interchange last year. 

That interchange has been labelled a "disaster" by experts after being plagued by traffic issues made worse by "confusing" signage. 

Speaking at a press conference on Friday, two days before the scheduled opening of the gateway, Minister for Roads John Graham flagged the exciting potential of this four-year project, going as far to describe it as the "ultimate Father's Day gift", and said lessons from Rozelle would make for a smooth transition. 

"This is a smaller change to the traffic network than the Rozelle Interchange, let's be clear about that," he said.

"We have learnt the lessons of previous openings, and we've asked drivers what they think of the line markings and signs ahead of time.

"However, local traffic impacts wouldn't be out of the question." 

Those intersections affected could potentially be in Botany and Arncliffe.

What is this new motorway? 

The Sydney Gateway is a toll-free motorway connection that links the M8 and St Peters interchange with Sydney's domestic and international airports.

The St Peters Interchange connects to the M8 as well as the M5 and M4, the main routes towards Western Sydney.

With its opening imminent, the state government has promised this $2.6 billion development will provide benefits to the city, namely a travel time of up to 17 minutes between airport terminals and the St Peters Interchange.

The streamlined travel time is helped by drivers encountering no traffic lights to the domestic terminal once they enter the M4.

It's estimated that 100,000 motorists will be using the motorway every day. 

But the NSW government said in July it also expects this new connection will mean fewer vehicles on local streets, providing an alternative route for roughly 10,000 trucks a day travelling to the airport and Port Botany.

School holidays will test road

The gateway is being opened during a quieter time of year for air travel to allow for drivers to get used to the road with limited traffic. 

"The next big period will be during the school holiday period, patricianly in the domestic terminal of the airport," Mr Graham said.

During the gateway's construction, Transport for NSW tested signage and road markings on members of the public, ordering 100 changes.

"We have learnt the lessons of previous openings, and we've asked drivers what they think of the line markings and signs ahead of time," Mr Graham said.