Campaigners delivered a petition on Thursday signed by 1,500 people opposing NHS cuts.
The members of Keep Our NHS Public (KONP) handed the petition to health chiefs during the annual general meeting of the five NHS primary care trusts in South West London.
Proposals are being made under the Better Services, Better Value (BSBV) review to close the maternity unit, A&E and the children’s ward in St Helier Hospital, Sutton.
KONP members have said the proposals will put increasing pressure on St George's Hospital, Tooting, and will mean poorer services for patients.
In a BSBV report published online Dr Ros Given Wilson, medical director at St George's Hospital, said: "There is a national and local shortage of staff specially trained to care for children and experts including the Royal College of Paediatrics and Child Health recommend that it is not possible to continue with the same inpatient children's services that we have currently.
"The quality of care for children who need to stay in hospital cannot be maintained on four hospital sites across south west London."
June Hautot, 75, a KONP member who lives in Tooting, made headlines earlier this year when she confronted Andrew Lansley about his proposed NHS reforms.
She said: "Unfortunately, I was right to be concerned. We will continue to alert the public to their devious actions.
"It is exactly what this Government has surreptitiously wanted for many years - to get rid of our precious NHS.
"It is still codswallop and I'm worried that it will get even worse under Jeremy Hunt's leadership."
The campaigners have said they will seek legal advice if the plans go ahead and will ask NHS commissioners to go back to the Government for more resources.
Sister newspapers the Sutton Guardian and Merton Guardian are running campaigns against the proposals to axe services at St Helier.
Their Save St Helier petition collected more than 1,720 signatures.