The NSW transport minister hasn't ruled out a hike in Opal fares after the next state election pending a review of prices on the back of "improvements" made to the transport system.
Andrew Constance has asked the Independent Pricing and Regulatory Tribunal to determine the "appropriate maximum fares" for Opal public transport services until June 30, 2024.
It follows a 2.2 per cent rise to Opal fares on July 2. The increase, which is in line with NSW's inflation rate, will stand until June 2019.
When asked on Thursday if fares would be increased after the 2019 state election, Mr Constance didn't confirm or rule it out.
Instead, he said it was a requirement IPART reviewed fares every five years.
"We've had fare freezes, had slight increases in the line of inflation ... and people are jumping on public transport because it's affordable," Mr Constance told reporters in Sydney.
"It's cheaper than using your car."
He noted the government didn't go ahead with IPART's proposal to bump up fares by 4.2 per cent earlier this year.
In his submission, Mr Constance said the government's "improvements" to the public transport network warranted consideration with Sydney Metro, light rail and on-demand services on the way.
The submission asks IPART to take into account the "costs and level" of Opal services when considering the "relative contributions" customers should make.
Labor's transport spokeswoman Jodi McKay said the government needed to be transparent and tell the public how much they would be paying for transport beyond June 2019.
She's concerned Opal fares could increase substantially given road tolls have increased almost twice the inflation rate.
"It's a cost of living issue, people are already paying massive tolls," Ms McKay told AAP on Thursday.
"Public transport needs to be affordable."
Mr Constance has asked IPART to deliver its determination no later than February 28, 2020.