Mr Johnson has previously questioned Labour rival Ken Livingstone‘s ability to deliver a promised 7% fares cut.
However Johnson recently suggested that a cut could be delivered in the new City Hall term by reducing costs within Transport for London.
Opinion polls suggest a sizeable number of voters believe fares should fall.
Asked about the apparent change of position, Mr Johnson told BBC London News: “There is certainly room to make sure we modernise, that we automate the system, that we take out cost and that we hold fares down in an honest and sustainable way.”
Pushed on the fact that automated trains would not arrive for a decade and could not therefore provide savings in the new term, Mr Johnson claimed almost half the Tube network would be capable of running “driverless trains” by 2014.
As Mayor Mr Johnson is Chair of Transport for London which has a business plan to implement fare rises 2% above inflation.
On Tuesday Mr Livingstone claimed Johnson had a “secret fares plan” which would see TfL “increasing the burden on fare payers” in order to help central Government cut the level of funding it provides to London.
Asked by presenter Riz Lateef if he thought he was “being fair to Londoners” in not confirming his fare policy, Mr Johnson said: “No Mayor ever commits himself to a fares policy more than a year in advance because it depends on what the circumstances are.”
Despite leading in the opinion polls and outperforming the Conservative party, Mr Johnson claimed the election is “a very tight race” between him and Mr Livingstone.
Londoners go to the polls this Thursday (3rd May) to elect a new Mayor and the 25 members of the London Assembly.
Candidates for Mayor include Jenny Jones (Green party), Ken Livingstone (Labour), Lawrence Webb (UKIP) Boris Johnson (Conservative) and Brian Paddick (Liberal Democrat). A full list of candidates can be found here.
Candidates standing as London Assembly constituency members can be found here. Candidates for the 11 Assembly London-wide seats can be found here.
