The poll of 1,004 GPs found 93% had faced pressure to prescribe the drugs, with 44% admitting to having prescribed antibiotics simply to get the patient to leave the surgery on at least one occasion.
A quarter of GPs (24%) said they had prescribed antibiotics when unsure about medical necessity because of a lack of easy-to-use diagnostic tools.
The findings highlight the difficulties associated with reducing antibiotic use to tackle the problem of rising antibiotic resistance at a time of high demand on general practice.
The survey was organised by the charity Nesta, the organisation behind the £10m Longitude Prize, which was recently awarded to tackle antibiotics resistance following a public vote.
London GP Dr Rosemary Leonard said: 'These results show the pressure GPs face to prescribe antibiotics when they aren’t necessary, something I understand very well.
'The more antibiotics taken, the more resistant bacteria become to them. Antibiotic resistance is a real issue and more needs to be done to conserve antibiotics for the future. Diagnostics play a valuable role in making this happen. Not only can diagnostics help determine the type of infection someone has, they could gather valuable data and aid the global surveillance efforts.'
Tamar Ghosh, lead for the Longitude Prize, said: 'Across the globe we need accurate point-of-care diagnostic tools to maximise the chances that antibiotics are only used when medically necessary and that the right ones are selected to treat the condition. In the next five years, the Longitude Prize aims to find a cheap and effective diagnostic tool that can be used anywhere in the world.
'We recognise that stemming the misuse and overuse of antibiotics is just one piece of the jigsaw to slow bacterial resistance to antibiotics. Nevertheless it’s an important step when we could be waiting many years for other solutions, including novel alternatives to antibiotics coming to the market.'
The UK's CMO Professor Dame Sally Davies has warned that growing resistance to antibiotics poses a 'catastrophic threat' to modern medicine. Last year the government launched a five-year antimicrobial resistance strategy to combat the problem.