Transport for London (TfL) has confirmed that it is pressing ahead with planned changes to routes 45 and 59 despite widespread concern from local people in a consultation.
Route 45 currently runs between Elephant & Castle and Clapham via Camberwell and Brixton.
But its timetable will now be amended during February next year so that it instead travels between Camberwell and Morden.
The changes have been proposed so that the route can replace the 118 between Brixton and Morden, which will be scrapped at the same time.
To maintain bus services that would otherwise be lost between Clapham Park and Brixton Hill under the changes, the timetable of route 59 will also be altered.
In Streatham, it will now run between Smithfield, St Bartholomew’s Hospital and Clapham Park/Atkins Road.
Currently the route runs between Smithfield, St Bartholomew’s Hospital and Streatham Hill/Telford Avenue.
TfL has claimed the changes are necessary because not enough customers were using route 45 between Brixton Hill and Streatham, and between Camberwell and Elephant & Castle.
Transport bosses believe the proposals will “simplify” the network between Streatham, Brixton and Camberwell.
Concerns raised by respondents to a TfL consultation about the changes include overcrowding on the new route 45 and route 59 no longer serving Telford Avenue, Streatham.
TfL has said that it has estimated that only two more passengers would board each 45 bus after its new timetable comes into effect.
Overall, 242 of 544 respondents said that the proposals for route 45 would have a negative impact, more than double the number who said the impact would be positive.
For the route 59 changes, 252 of 542 respondents opposed the plans, compared to 67 people who viewed them favourably.
Responding to the concerns raised, TfL said: “Customer demand for buses has fallen in inner London in the last few years.
“We considered these proposals represent a better match of bus capacity with passenger demand, that will help encourage more use of public transport, while continuing to provide regular and reliable bus services to popular destinations in the area.”