Of 401 GPs who responded to the poll, 67% said they did not feel their practice was adequately prepared to deal with the emerging outbreak.
More than half of GPs (53%) said practices had not received adequate guidance and information about COVID-19 - and just one in five (21%) said their practice had the equipment needed to manage an outbreak, including supplies of personal protective equipment (PPE).
GPs warned that with pressure on practices already high, a surge in workload from coronavirus would leave many struggling to cope - particularly if practices were left short-staffed as individual doctors were forced to self-isolate.
GPonline revealed this week that most GPs believe suspension of routine appointments will be necessary as the outbreak grows - and around half say the QOF should be suspended immediately to spare practices the heavy workload involved in entering achievement data in the run-up to 31 March.
NHS England has promised to start deliveries of PPE this week, but a growing number of practices have already faced possible cases - with at least 30 forced to close temporarily in recent weeks following contact with patients who may be infected.
Most practice closures have lasted for a matter of hours - although one 20,000-patient practice in Devon was shut down for a fortnight after all staff were placed in isolation.
The survey findings came as the total number of cases in the UK rose to 319 on 9 March, with five deaths confirmed. Prime minister Boris Johnson has said the UK will see a growing number of COVID-19 cases and that there is 'no hiding from the fact that the coronavirus outbreak will present significant challenges'.
One GP responding to the GPonline poll said coronavirus posed 'a significant and imminent threat which the NHS cannot and will not cope with'. The GP added: 'Its knock-on effects to routine and other urgent health will be unprecedented if it truly becomes pandemic.'
Another respondent said: 'If the plan is to contain it until the quiet summer months as stated in the last government release, not sure what planet they are on if they think summer is any less busy. It just takes one case walking in to shut the practice for a day as well.'
One respondent said: 'We are small practice with two GPs - what is going to happen if GPs are off work? If my partner is off and I have to run the practice by myself I would likely last four weeks before I am overwhelmed.'
Several GPs said workload pressures had been increased by NHS 111 inappropriately directing patients with possible coronavirus infections to their practice.
How to care for patients who may be infected with COVID-19 was also an issue GPs said they needed more advice on. One wrote: 'The problem I foresee is that patients awaiting coronovirus results or who have tested positive will still want healthcare. I have heard of a patient who whilst awaiting swab results called with concerns that they had a thrombosis. How do we deal with that? What about a suicidal patient in a similar situation?'
A pregnant GP said she was concerned about the standard of advice she had received from Public Health England (PHE) about whether to continue working. 'I am pregnant,' the GP wrote. 'I queried the guidelines for pregnant healthcare works with PHE and was told to "avoid contact with anyone who is unwell". Not very practical as a GP.'
Another GP said that for locums there had been a 'total lack of information' and that doctors not linked to specific practices had to seek out the correct guidance.
Several GPs responding to the survey, however, warned against panic. One said: 'I still do not understand what the major panic is. More people have died of old age in my small practice in the last month than of coronavirus.
'We are predominantly a retired population so potentially high risk, and most of the local surgeries are reliant on locums to prop them up due to national GP partner shortages. Panicking people into thinking the end of the world is coming helps no one, explaining good hand hygiene is the only good thing to come out of this pandemic so far.'