Some outpatients saw their appointments at West Middlesex Hospital postponed as doctors took part in a one day strike.
The hospital said it planned for the industrial action in advance and medics still provided urgent care on Thursday, June 21.
Kingston Hospital also said the strike would not affect emergency cases but it did need to rearrange some routine appointments.
Doctors took industrial action for the first time in nearly 40 years after the British Medical Association accused the Government of unjustifiably forcing them to increase their pension contributions.
However, NHS South West London warned medics about their contractual obligations to the NHS and their patients.
A spokeswoman for West Middlesex Hospital said: “We would like to apologise for any inconvenience caused.”
The hospital contacted affected patients by phone and in writing and will arrange alternative dates for appointments from next week.
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