Premier Gladys Berejiklian has coined the term "toll mania" while defending tolls on the new M8 and existing M5 East motorways.
New, eight kilometre twin tunnels tollway from Kingsgrove to St Peters are expected to be opened quietly on Sunday morning, in sharp contrast to the public walk-through attended by thousands when the M5 East opened in 2001.
Premier Gladys Berejiklian and Deputy Prime Minister Michael McCormack inspected the $4.3 billion project on Wednesday.
While answering questions from the media, she laughingly said, "What did you call it, 'toll mania'? - It's a good line".
But motorists who intend to continue to use the M5 East to General Holmes Drive at the Airport are not laughing.
There is growing anger they will be tolled even though it was made clear when the M8 - originally called the New M5 - was announced five years ago.
The toll on both roads will be $6.95 for cars and $20.86 for trucks.
NSW Labor "slammed the Premier's commitment to 'toll mania' and urged the government to introduce a toll-free period on the M8 and scrap the new toll on the old M5 East".
"It will take people time to adjust to the new road, and people will want to explore the route and see if it works for them," said Labor's spokesman on roads John Graham.
"It's just greedy to throw a toll at motorists the second the road opens.
"The M5 East has been free since it opened in 2001 and there have been no upgrades.
"Sydney has become one of the highest tolled cities on earth.
"It's going to hurt motorists, families on tight budgets and it's going make it even harder for tradies and truckies to do business."
Ms Berejiklian said, "I know that when motorists use this for the first time they will be pleased with the travel time savings, pleased with the convenience".
"We're building a network which is efficient, which saves time, which is safer and above ground it reduces congestion and pressure."
Transport Minister Andrew Constance said tolls "enable this infrastructure to be built generations ahead of time".
A Transport for NSW spokesman said the M8 tunnels would double the capacity on one of Sydney's most congested routes.
"This change was first announced in 2015 as part of the planning and community engagement for this vital $4.3 billion project. The M5 East was not built to handle the number of cars and trucks that rely on it daily.
"The M5 East carries about 100,000 vehicles a day, and the toll reflects the significant travel time improvements many of these motorists will experience as a direct result of the M8.
"For example, motorists will save up to 30 minutes between Liverpool and South Sydney, with average travel times halved and peak hour speeds doubled.
"To prepare for the M8 a number of surface and in-tunnel works have been completed, including major surface works at Kingsgrove and resurfacing of the M5 East tunnels.
"WestConnex will have a capped, distance-based tolling system, which is a fair and equitable system made possible by electronic tolling. This means motorists will only pay for the section of motorway they use.
"When the entire WestConnex project is finished the toll will be capped at $9.68 after about 16km."
The spokesman said toll prices were set in long-term, legally binding contracts between the NSW government and motorway companies.
"This funding approach has reduced our contribution on motorways that keep vehicles including freight moving across our State.
"It's also freed up capacity to invest in other essential services such as hospitals, schools and public transport.
"Tolls on motorways help accelerate investment in major roads, delivering travel time savings and lower operating costs which boosts economic growth."
The M8 will open with two lanes in each direction but has capacity to upgrade to three lanes, and include connections to future projects including the M4-M5 Link Tunnel, M6 Stage 1 and Sydney Gateway to the airport and Port Botany.
WestConnex, costing a total of $16.8 billion, is being delivered in four major stages, including the New M4 (now open), the M8 and the M4-M5 Link Tunnel and Rozelle Interchange, opening in 2023.
When complete, WestConnex will provide drivers with a 33km road network, bypassing up to 52 sets of traffic lights.