Funding for the reform would come from slashing the cost of competition in the NHS, Labour says.
Speaking in Manchester, Mr Miliband said the party would put its plans for the health service at the heart of its 2015 general election campaign.
The proportion of patients who manage to see a GP within 48 hours has dropped from 80% under the last Labour government to just 40% now, Mr Miliband said.
Labour would reinstate the 48-hour GP access target first put in place under Tony Blair’s government, guaranteeing patients a GP appointment within 48 hours, and the right to book appointments with a named GP further ahead.
The plans would also allow patients to consult a doctor or nurse at their surgery on the same day, and to secure a same-day appointment at the surgery if necessary.
Labour would invest £100m to achieve the change, much of which it plans to recover by cutting back on NHS competition.
Mr Miliband said his party would scrap government regulations that ‘have led to spending of at least £78 million on unnecessary administration and legal fees because NHS services are now under threat from EU competition law’.
GP investment to cut A&E costs
The Labour leader claimed that the additional investment in general practice could enable an extra 3m appointments a year, and slash visits to A&E, generating up to £300m additional savings.
Mr Miliband said: ‘We will restore the fundamental values of the NHS, end David Cameron’s dogmatic obsession with competition and privatisation, and reduce the huge costs that have come about because of it.
‘We’ll clamp down on the competition lawyers, bogging down the NHS and distracting from patient need - and we’ll put £100 million of the savings these changes make straight back into improving GP care.’
RCGP chairwoman Dr Maureen Baker said: ‘There is a growing crisis in waiting times to see a GP across the country, and it is clear that this will become a key issue at the next election.
General practice in crisis
‘GPs want to provide better access for their patients, but are being prevented from cutting waiting times because of the funding black hole in general practice. Ed Miliband’s announcement that more money should be channelled into general practice is therefore extremely welcome.
‘We are pleased that politicians are starting to sit up and take notice following six months of campaigning by the college to bring attention to the fact that general practice is now teetering on the brink of collapse.’