The plea comes alongside new findings by NHS England that four in ten people are too concerned about being a burden on the NHS to seek help from their GP.
Seeking medical help is one of the four reasons that people can safely leave home, in line with government guidance linked to measures introduced following the coronavirus outbreak.
However, A&E attendances have dropped by around half in less than two months. Figures from Public Health England for the week ending April 19, show around 7,500 people a day now turning to A&E department. The figure was around 14,000 at the start of March.
Merton GP and Chair of the South West London Clinical Commissioning Group, Dr Andrew Murray said:
"We know some people will be worried that by contacting their local surgery they'll be putting extra strain on the NHS - but GPs want people to get in touch about significant health concerns before they get worse.
Don't wait to seek help, if you need advice from your GP contact your practice in the way you normally would. Ignoring problems can have serious consequences - now or in the future."
People are being urged to contact their GP or the 111 service if they have urgent care needs - or 999 in emergencies - and to attend hospital if they are told they should. GP practices will be open as normal this bank holiday Friday, 8 May.
The NHS is also reminding people that other vital services should be used as they normally would - such as cancer screening and care, immunisations, maternity appointments and mental health support.
Wandsworth GP Dr Nicola Jones said:
"GPs are working in different ways to support patients while reducing their need to travel - we can help with lots of issues over the phone or using video consultations.
If you do need to come to your practice or we need to send you to hospital for further tests, the NHS has made changes to ensure patients who don't have Covid-19 can access services safely."
Across the country and locally in South West London the NHS has significantly increased its capacity and combined with effective social distancing by the public to slow the spread of the virus, this has meant that the NHS has so far successfully been able to meet everyone's need, with capacity to spare.
Kingston GP Dr Naz Jivani added:
"Your GP practice is here for you if you are worried about you or your family's health - for example if your child is unwell or you need help with managing a long term condition.
It is vitally important that if people have serious conditions or concerns they seek help. This campaign is an important step in ensuring that people are encouraged to get the care they need when they need it."