Morgannwg LMC secretary and locum GP Dr Ian Millington praised local practices and the NHS for their response to the measles outbreak.
He told GP that vaccination clinics and extra consultations had led to real pressure on services at a time of high workload in general practice.
'GMS contract work is pretty busy at the moment. The strain is really quite large; general practice is pretty resourceful but it's limited at the moment. Colleagues are working flat out to deliver this, including practice nurses and receptionists.
'Because general practice is a demand-led service, it's extremely difficult to postpone day-to-day stuff.'
'What really worries me, as GMS contract work piles on, is that general practice’s ability to respond will be limited. If the squeeze [on workload] is hard, it can’t deliver during an outbreak: we don’t have enough reserve in the system.’
Dr Millington believes measles could appear in any area where immunisation levels have fallen below that required for herd immunity. He said: 'I think there is a risk it will spread. Practice in areas where immunisation levels are low may need to think about the response they could give should an outbreak occur.
Patients who attended the first the mass vaccination clinics in Swansea are now due a second dose - and will be heading to their local surgeries soon.
Dr Millington said he wasn't sure how practices are going to cope with that demand, although talks with the local health board are underway.
Health officials announced on Thursday that GPs are to lead a national MMR vaccination programme to protect 1m children against measles.
The £20m catch-up programme will target 300,000 children aged 10-16 years who have not received the MMR vaccine, in a bid to halt the continuing outbreak. A further 700,000 children require a second dose for full protection.
Cases in England rose to 587 in the first three months of 2013, while 942 cases have been reported in Wales.
RCGP immunisation lead Dr George Kassianos said: ‘The prospect of seeing measles outbreaks in different areas of the UK is real. We need to prevent this from happening. If necessary, we should open on Saturdays just for MMR vaccinations.’
Despite the workload concerns, NHS England’s head of primary care commissioning, Dr David Geddes, told GP the vaccination campaign should not significantly raise practice workload as the bulk of the campaign would be centrally organised and co-ordinated.