All bendy-buses in London have been taken out of service following three separate fires on the vehicles.
At least three bendy-buses have caught fire in the last three months
The 130-strong fleet will not be in operation for a week to allow "modification" work.
An inquiry was launched following the latest incident, when a number 436 was gutted after bursting into flames on Park Lane on Saturday night.
The passengers and driver escaped unharmed, but it was the third fire on the £200,000 buses since December.
Hans Smits, managing director of manufacturer Evobus UK - part of the Mercedes group - said: "Based on the results of the technical investigation into the Mercedes Benz Citaro bendy bus fire of last Saturday, Evobus have decided that certain modifications to all Citaro buses in London are necessary."
A hose used in the bus engines has been identified as the problem.
According to Evobus, the Citaro is the biggest selling city bus in Europe and is also used by operators in Coventry, Birmingham, Manchester, Oxford and Berkshire.
The Oxford Bus Company has announced its withdrawing 17 Ciatro standard buses following concerns about the fires in London.
The single deckers will be taken out of service for modifications but are expected to be back on the road on Thursday.
Modifications are being made, after examination of the wreckage
Travel West Midlands said its 10 bendy-buses in Coventry and one in Birmingham were a different specification to those in London.
A spokesman said they had been closely following the situation there and had spoken to Evobus but were confident a similar fault would not occur on their fleet.
Bendy-buses in London were taken out of service following a meeting of representatives from the company, Transport for London (TfL) and bus manufacturer Evobus on Tuesday to discuss the situation.
On Monday, it was announced special fire-suppression equipment would be fitted to the buses and that all the vehicles would have to be checked by staff before they leave the depot.
The Park Lane incident followed two other fires on buses in service - one at Edgware Road and another at Camberwell.
Peter Kavanagh, from the Transport and General Workers Union, said: "Our members and the travelling public will be reassured that their safety has been put at the top of the agenda.
As well as the 130 bendy-buses, a further 20 short "single deck" Citaros have also been withdrawn for modification. A spokesman for TFL said work would start on the buses on Wednesday morning and "should be completed within a week".
There are no services on the 436, 453 and 521. Reduced services are operating on the number 18, 293, 507, and RV1 have been replaced by ordinary buses.
Extra services are running on routes 36, 53 and 185.
At about 0645 GMT on Wednesday a number 19 Routemaster bus caught fire on St John's Road in Angel, north London. No-one was injured.