People who travel on Sydney's light rail line will be able to pay for trips using their Opal card from next week.

The public transport smartcard will be available on the line, which runs from Central to Dulwich Hill, from Monday, December 1, well ahead of the government's previously scheduled start date of early 2015.

On track: Light rail users will be able to tap on from December 1. Credit:Tamara Dean

The Opal card will also offer a different fare structure than the paper tickets, which will continue to be sold.

Individual fares will be cheaper using the Opal card, while the "zones" used to calculate fares will also change for the card.