Paper tickets will no longer be sold or accepted on the New South Wales public transport network from today, with the Opal card being the only ticketing option available.

Key points: Almost 8 million Opal cards issued since 2012

Almost 8 million Opal cards issued since 2012 Concern for homeless, disadvantaged having difficulty with system

Concern for homeless, disadvantaged having difficulty with system Calls for dedicated tourist card

The State Government said 350,000 Opals had been sold in the last month in anticipation of the change, with almost 8 million issued since its introduction in December 2012.

"I think everybody will be happy to see paper tickets go actually," Opal spokesman Alastair Walton said.

"The Opal card is so much more convenient."

The Government said while 95 per cent of public transport users have an Opal, some will still be caught out today.

"So we are asking for people to have patience because there may be queues at ticket machines or queues at staff [desks] asking about what to do for those people adjusting to this transition," Mr Walton said.

More than 2,000 retailers sell Opal cards for adults and children or youth.

But those needing a Gold Opal — the discounted concession travel card for seniors and pensioners — have to apply online or on the phone and have it sent to their home.

Homeless, disadvantaged people may be left unable to travel

Manager of the Wollongong Homeless Hub Julie Mitchell said due to that process there are going to be many of New South Wales' homeless and transient population as well as other people from disadvantaged circumstances left with no way to get on public transport today.

"The procedure is quite involved, people need to go online, and it takes about 15 to 20 minutes to do this and it takes a certain amount of literacy skills and computer skills," Ms Mitchell said.

"They don't have an address because they are transient, they are homeless or they are sleeping rough and unless they know a centre such as ours where they can get their mail sent to, it's going to be very difficult for them to do this process."

The Wollongong Homeless Hub, like many other charities, used to provide single bus or train tickets to their clients or provide them with $2.50 for a fare, but now that cannot happen.

"Transport [NSW] have been working very closely with the charities and NGO sector on these issues where they help out that group of people who don't have a permanent home [and] may have some difficulties holding on to things," Mr Walton said.

The State Opposition wants the system changed to allow for single-use concession cards to be purchased on the spot.

"You couldn't devise a system more riddled with more bureaucratic complexity," Opposition Leader Luke Foley said.

"I don't know why we are making it harder for the most vulnerable people in our society."

Calls for dedicated tourist card

The Transport and Tourism Forum is calling on the State Government to introduce a dedicated transport card for visitors, similar to ones issued in London, Paris and Stockholm.

The Forum believes that such a card would simplify transport for visitors because it's hard for tourists to know how much money to put on their Opal with little knowledge of Sydney's transport fare structure.

"One of the things that we know that, probably at the top of the list for people visiting any city in the world, is a great public transport system that's easy to access," President Margy Osmond said.

Single-use Opal cards will be available for bus trips at a premium and can be bought from the bus driver, but the Government only wants them purchased as a last resort.