The Lady Herron was towed into the port yesterday afternoon to tie up at the Snakepit berth in Carrington, a few hundred metres upstream from where she was built in 1975 at the State Dockyard.

The tug that brought her to Newcastle, Molly Grace, is scheduled to return today with the other ferry, Lady Northcott, built at Tomago's Carrington Slipways in 1975.

Transport for NSW said yesterday that the Lady Northcott and Lady Herron had been the two oldest vessels in Sydney's ferry fleet when they were retired in October 2017.

"They had reached the end of their working lives and were very expensive to keep in service," a Transport spokesperson said. Maintenance costs were five times newer vessels, which cost half as much to operate.

After years of controversy over the cost and reliability of Sydney ferries, the NSW government "franchised" the service in 2012, with the French company Transdev winning a seven-year contract that was extended last year for another nine years.

Transport said the ferries were likely to stay in Newcastle for six months while a sale was arranged through marine brokers IBS Global.

The Snakepit berth is operated by another French company, Thales, which built the Royal Australian Navy's Huon class minehunter vessels there between 1994 and 2003.

Thales took over the site again in 2017.

A tradition of naming Sydney ferries after the wives of NSW governors began in 1892, with Lady Herron the 20^th such vessel.

Wooden vessels gave way to steel hulls in 1968.

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