From Friday, the Opal ticket can be used at 55 more stations between Wyong, Strathfield, and the city loop, on all ferries and two bus routes, Transport Minister Gladys Berejiklian told reporters at Redfern station.
If Friday's rollout "goes without a hitch", further expansions of the system could be brought forward, Berejiklian said.
The Opal ticket system is expected to be in place across all networks by the end of the year.
"This will really change the way [people] catch public transport," she said.
Fares on the Opal card have been discounted by between 13 and 6 percent, and after eight journeys in a week, additional travel is free.
"At least 90 percent of our customers have the potential to be better off," the minister said.
About 56,000 Opal cards have been registered, and more than 2 million trips have been made using them.