Opal card push for Sydney buses

Now that Sydney's Opal card system has been rolled out across the city's train network, the government will focus on putting it into buses.

The electronic public transport ticket system, which offers cheaper fares for regular users, is "live" at 308 suburban and intercity train stations and on all ferries between Manly and Parramatta, NSW Transport Minister Gladys Berejiklian said on Friday.

"We're now shifting our attention to buses and from Monday, April 14, customers on 24 bus routes in northern Sydney's Ku-ring-gai and Hornsby region will have access to all the benefits of the Opal card," she said in a statement.

The rollout was scheduled to be finished by the end of the year.

While it's progressing ahead of schedule, Ms Berejiklian warns that finishing the rollout across more than 5000 buses "is the most challenging phase, technologically and operationally".

About 6.5 million trips have been paid using the Opal card, of which 170,000 have been registered.