The payment of public transport trips by using a credit card or mobile phone is expected to be expanded to Sydney's ferry fleet as early as February, following successful trials on services between Manly and Circular Quay.

The likelihood of a quicker-than-expected rollout of electronic payment technology could open the way for the system to be expanded across Sydney's public transport network by the end of next year.

Sydney's ferries will be the test for cashless payments for trips across other public transport networks.

The Manly ferry route has been the testing ground for commuters to use Mastercard credit and debit cards to pay for their journeys to and from Circular Quay since July.

The so-called contactless technology is expected to be rolled out to light rail services after the city's ferries, and then to the much larger rail and bus networks.