The largest ferry operator in the country says it could carry another 1.5 million passengers a year in a push to improve Auckland's public transport system.
However, the Fullers Group, whose 10 ferries carry four million passengers a year on 42,010 sailings on Auckland's Waitemata Harbour and the Hauraki Gulf, said new routes, new wharves, additional feeder buses and park and ride services would be needed.
Fullers chief executive officer Doug Hudson said that as roads became more congested and environmental concerns increased, ferry travel was "enjoying an international renaissance".
He said ferry services in Auckland compared well with those in Sydney and Brisbane, which received a far greater operating subsidy.
Auckland ferry services received a subsidy of $3.6 million a year. With 4.2 million passengers annually, that meant a subsidy of 84c a passenger.
Buses carried 42.9 million passengers a year and received a subsidy of $1.59 a passenger, while rail carried 5.24 million passengers a year and received $6.64 a passenger.
Brisbane ferry operators got twice the subsidy of Auckland, and Sydney operators got seven times the subsidy of Auckland.
Mr Hudson said new routes could be down the East Coast Bays to Takapuna and into the city with new wharves at Browns Bay, Mairangi Bay, Murrays Bay and Takapuna.
There could also be services to both eastern and western suburbs.