"We urge London’s bus operators to see sense and collectively engage in talks to give London’s bus workers a fair deal."
But Mike Weston, Transport for London's director of buses, said it made "no sense" to pay drivers the same rates as they all have "different levels of experience".
He said increasing wages for some drivers would cost about £100million a year, resulting in cuts to services or an increase in fares.
In a statement, he said: “I am very sorry that the leadership of Unite are threatening to further disrupt the journeys of bus passengers, especially given that only 16 per cent of the bus drivers voted for strike action.
“As the bus companies who employ the drivers have said, it makes no sense to pay all drivers precisely the same amount. As in all professions, bus drivers have different levels of experience and it is only right that this can be reflected in pay.
"A ‘levelling up’ of pay to the highest rates would cost around £100 million a year and would result in a cut to bus services, an increase in fares, or both."
He continued: “London has one of the best and most extensive bus networks anywhere in the world. It would be much better if the leadership of Unite actually worked with the bus companies to ensure that it remains that way rather than disrupting bus passengers.”
