Services were suspended across Greater Sydney and the intercity network early Monday morning, affecting routes from Newcastle, the Blue Mountains and Kiama on the South Coast.

Anneke Borger was preparing for her first day at the University of Newcastle, but with no option to travel to campus she was forced to miss her first class.

"It is impossible for me to get from the Central Coast to Newcastle just so I can go to class," she said.

"My housemates are all in the same position and today is our first day of class and while I am sure it will be considered a reasonable excuse if I do not show up it is my first day of university ever and I am not even going to be there after looking forward to it for so long."

Commuters were advised to use alternative modes of transport and allow extra travel time, but commuter Sophie Bert was over an hour late to work because of the cancellations.

"It is the first day of the week and a lot of people will also be returning to the office for the first time in CBDs where surrounding hospitality venues really need people coming back," she said.

"They have just disrupted many peoples attempts to return to work in what is the first time in a long time and I am just lucky I do not have a meeting or something that I had to be at over an hour ago."

It came after a long-running dispute between the government and the Rail, Tram and Bus Union over safety guarantees, hygiene and privatisation concerns.

The dispute was before the Fair Work Commission on the weekend and the decision was to cancel trains around midnight.

But the union said workers are not on strike and are undertaking two weeks of protected industrial action that would not have impacted commuters.

Shadow minister for regional transport and roads Jenny Aitchison said in a tweet that train drivers were ready to work, but they had been turned away.

"Massive congestion in Maitland and Hunter today, but Train drivers didn't go on strike. They turned up to work for 2am," she tweeted.

"The NSW Government cancelled the trains and locked out the workforce."

The Australian Manufacturing Workers Union NSW state secretary Cory Wright said the cancellations were unnecessary.

"These workers deserve everything they are fighting for: proper safety protections, a decent pay rise, a fair disciplinary process and a rostering system that allows for workers to have a work-life balance."

The matter returned to the Fair Work Commission on Monday.

IN THE NEWS:

Our journalists work hard to provide local, up-to-date news to the community. This is how you can continue to access our trusted content: