Train fares for Illawarra rail commuters would be slashed almost in half if the government adopted a proposal from the Rail, Tram and Bus Union.
The plan scraps the current distance-based model in favour of one that calculates fares based on socio-economic status factors like income, education and occupation.
Broadly speaking, the union's plan would mean those who lived further away from the Sydney CBD would pay less than those closer in.
Commuters who caught a train to Sydney from any station in the Illawarra - classed as Zone 2 - would pay just $4.60 instead of the current $8.60, and towns in the Southern Highlands would pay even less - just $3.80.
As fares would be calculated based on where the trip started, these fares would remain the same no matter how far someone travelled.
So a trip from Wollongong to Sydney, the Central Coast or Newcastle would all cost $4.60.
For shorter trips, there is a five-kilometre rule where the fare would be no more than $3.80.
Rail, Tram and Bus Union national secretary Bob Nanva said the "Fare's Fair" report was inspired by a number of members - including some in the Illawarra - who had complained about the "inequity" in the fare structure.
"It's no good turning a blind eye to the fact that the people from the Illawarra are paying, as a proportion of their salary, four to five times the amount to get to work that someone from the North Shore is," Mr Nanva said.
The union report says there has been a decline in rail use and Mr Nanva said this fare overhaul would make catching the train more attractive.
"We think that if you change the fare structure there will be a marked increase in patronage," Mr Nanva said.
He said the model is a lot fairer.
"It effectively means we would see more people using public transport because they aren't slugged for living further out of the CBD, like they are currently."
The proposal has won the support of Shellharbour MP Anna Watson, who said the government needed to look at it.
Mr Nanva said the union planned to present the report to Transport Minister Gladys Berejiklian later this month.
Mrs Berejiklian declined to say whether she would consider the proposal, instead choosing to highlight the Opal card system.
"Opal is now active on all Sydney Trains and NSW TrainLink Intercity services, giving customers cheaper fares, travel incentives and the benefit of never having to queue for a ticket again," Mrs Berejiklian said.
She said improvements are getting more people onto public transport.