No paper public transport tickets beyond single and return tickets will be sold from next year, Transport Minister Andrew Constance said on Tuesday morning.

The decision to stop selling most types of paper tickets means up to half a million pensioners and seniors will have the next five months to sign up for a Gold Opal pass, or otherwise be left paying regular concession fares.

In his announcement on Tuesday, Mr Constance also foreshadowed the eventual closure of all types of paper tickets, and said the government was looking at whether to upgrade the Opal system to allow payment by "contactless" credit card or smartphone.

Among the 57 types of tickets that will not be sold from January 1, 2016, are the commonly used TravelTen for buses, Pensioner Excursion Ticket, and Family Funday Sunday tickets.

"There is no point continuing to run two ticket systems," said Mr Constance, who lauded the widespread take-up of the Opal card as one of the signature successes of the Coalition government.

About 70 per cent of all public transport trips are now made using an Opal card, and 3.3 million cards have been issued since the system began on ferries in December, 2012.

Mr Constance said the government would retain adult and concession single or return paper tickets for trains, ferries and light rail, and single tickets for buses.

He said a decision had not been made about when to also retire those tickets, but the day would come.

"Transport will keep an eye on it, and then phase it out at the appropriate moment."

But the closure of paper-based tickets will mean a change for hundreds of thousands of pensioners who have not signed up for the Gold Opal.

Seniors need to apply for this card, under which they are charged the same as those using a Pensioner Excursion Ticket, and provide their Pensioner or Seniors Card to prove they are eligible for it.

"We've seen 370,000 seniors seniors take it up, and we believe there's somewhere in the order of 300,000 to 500,000 seniors who will need to transition to the new Gold Opal over the next five months, which is why we will continue to promote it in our shopping centres, across the community," Mr Constance said.

Amelia Christie, manager of research and advocacy at the Combined Pensioners and Superannuants Association, said there were multiple reasons some seniors did not want to sign up for a Gold Opal card.

"We would like to see both systems remain in place," Ms Christie said.

"The people who we are speaking to, they don't want to have automatic top-up," she said. Some were concerned that bank accounts might be overdrawn, while other seniors were concerned about the lack of an ability to travel anonymously with the Gold Opal card.

"And there's still not going to be top-up machines at all stations," she said.

With most public transport users having adopted the Opal, sales of other paper tickets have dropped dramatically. For instance, there were 83,120 MyBus TravelTen tickets sold in May, about 76 per cent fewer than were sold last year.

Transport authorities in London, whose Oyster card provided the model for the Opal, have introduced upgrades allowing public transport users to pay for journeys directly through contactless credit cards. London authorities have said it could take about two years to introduce similar upgrades in Sydney, and Mr Constance said he was interested.

"The future in this regard is incredibly exciting," he said. "We could see the advent of account-based ticketing very, very soon, it's rolling out elsewhere around the world, where people can tap on with their smart phones, tap on with their credit cards and tap off with those products as well.

"I've asked Transport to look very closely at that. I think the future lies in the of use of technology to improve the customer experience."

Labor's transport spokeman, Ryan Park, said only one in six train stations had Opal top-up machines.

"Let's hope that the half a million elderly people who are still using tickets are not left behind by the minister's race to grab a headline," Mr Park said.

Correction: An earlier version of this report incorrectly stated that pensioners without a Gold Opal from next year would have to pay full fares, not regular concession fares.